<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2021 Workiva-->
<!--r:e2468f17-c343-4912-8391-5ff322c24742,g:9ec18062-221e-4eed-bce3-7b7c044b7139-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/ConsolidatedStatementsofStockholdersDeficitEquity" xlink:type="simple" xlink:href="lii-20210930.xsd#ConsolidatedStatementsofStockholdersDeficitEquity"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/ConsolidatedStatementsofStockholdersDeficitEquity" xlink:type="extended" id="ic060ad1162c44d1e88a650f26ff2fb8e_ConsolidatedStatementsofStockholdersDeficitEquity">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_fc085782-6fa6-4f1b-b653-0cc334a382a0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_StockholdersEquity_fc085782-6fa6-4f1b-b653-0cc334a382a0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_901b19b0-8c4e-40a9-aa46-c393a54f6792" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_NetIncomeLoss_901b19b0-8c4e-40a9-aa46-c393a54f6792" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_bee9742c-7927-49fb-a1cf-073fc787142e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DividendsCommonStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_DividendsCommonStockCash_bee9742c-7927-49fb-a1cf-073fc787142e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_38c877c1-beaa-4525-ad63-fe25a306f0b1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_38c877c1-beaa-4525-ad63-fe25a306f0b1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_04ff5c19-02fa-4860-af12-884f833ea625" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_04ff5c19-02fa-4860-af12-884f833ea625" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest_390bbdd4-f75d-4829-baea-1859ad00ca7e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest_390bbdd4-f75d-4829-baea-1859ad00ca7e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_336a46ee-9e98-4d7a-b919-c0a9a49cc965" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_336a46ee-9e98-4d7a-b919-c0a9a49cc965" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax_e5137c54-eda4-43e1-a70f-fe6507f7b5a1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax_e5137c54-eda4-43e1-a70f-fe6507f7b5a1" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_3660d24a-be4b-499d-9fb8-12a663188e6f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_3660d24a-be4b-499d-9fb8-12a663188e6f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueTreasuryStockReissued_764cedf9-96fd-4dd6-bb19-72a136a3f68a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueTreasuryStockReissued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueTreasuryStockReissued_764cedf9-96fd-4dd6-bb19-72a136a3f68a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued_a717c589-0e72-48a4-a4f2-0771e88efecb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued_a717c589-0e72-48a4-a4f2-0771e88efecb" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_d4b7f207-8ff0-43e4-9987-430fae4622a5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TreasuryStockSharesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_d4b7f207-8ff0-43e4-9987-430fae4622a5" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_742a2d15-9d26-4cdb-a2b7-93df457b689e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_742a2d15-9d26-4cdb-a2b7-93df457b689e" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockShares_0f563b2f-4b4f-45ed-8d75-9adc3d62bc5e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TreasuryStockShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_TreasuryStockShares_0f563b2f-4b4f-45ed-8d75-9adc3d62bc5e" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_62b4ff5c-647d-4767-b163-476613a0edd9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdateExtensibleList_b5943971-0a50-43c9-8ec9-72fca041f1f2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountingStandardsUpdateExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_AccountingStandardsUpdateExtensibleList_b5943971-0a50-43c9-8ec9-72fca041f1f2" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_18da15a0-fefc-4ae4-886f-1866eb93312b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_EarningsPerShareDiluted_18da15a0-fefc-4ae4-886f-1866eb93312b" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Dividends_e43d384d-3ec9-4957-92e2-2df643b72509" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Dividends"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_Dividends_e43d384d-3ec9-4957-92e2-2df643b72509" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax_04a335fd-74fe-4557-9002-f907e2de9992" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationTax_04a335fd-74fe-4557-9002-f907e2de9992" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax_339ca4df-e18d-4d2c-b3b2-2613284ced65" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax_339ca4df-e18d-4d2c-b3b2-2613284ced65" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_5f2cbdf6-1b27-48cd-b2a0-616072fedcea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_5f2cbdf6-1b27-48cd-b2a0-616072fedcea" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_0f2768d7-772e-4ae9-8564-962600557d68" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_906f016b-a193-438d-91c2-ce29256a96ff" xlink:to="loc_us-gaap_StatementTable_0f2768d7-772e-4ae9-8564-962600557d68" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_e519a736-d5dc-4914-bda5-6dd30e84e908" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0f2768d7-772e-4ae9-8564-962600557d68" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_e519a736-d5dc-4914-bda5-6dd30e84e908" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_e519a736-d5dc-4914-bda5-6dd30e84e908_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_e519a736-d5dc-4914-bda5-6dd30e84e908" xlink:to="loc_us-gaap_EquityComponentDomain_e519a736-d5dc-4914-bda5-6dd30e84e908_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_5c7da100-9741-4567-aedb-3862eed77189" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_e519a736-d5dc-4914-bda5-6dd30e84e908" xlink:to="loc_us-gaap_EquityComponentDomain_5c7da100-9741-4567-aedb-3862eed77189" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_909346f6-2eb6-42e0-926e-68fcd5379c0a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5c7da100-9741-4567-aedb-3862eed77189" xlink:to="loc_us-gaap_CommonStockMember_909346f6-2eb6-42e0-926e-68fcd5379c0a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_27da69c8-2817-4709-9571-070241a6f40b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5c7da100-9741-4567-aedb-3862eed77189" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_27da69c8-2817-4709-9571-070241a6f40b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_2b2caf43-fc72-4951-ad5e-9e8f2da6a4d1" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5c7da100-9741-4567-aedb-3862eed77189" xlink:to="loc_us-gaap_RetainedEarningsMember_2b2caf43-fc72-4951-ad5e-9e8f2da6a4d1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_3e6b9a9d-3acd-478e-8832-df6edbd047c3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5c7da100-9741-4567-aedb-3862eed77189" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_3e6b9a9d-3acd-478e-8832-df6edbd047c3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockMember_844d17e7-f1dc-4c7f-83bd-5f8e0c3c227a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TreasuryStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_5c7da100-9741-4567-aedb-3862eed77189" xlink:to="loc_us-gaap_TreasuryStockMember_844d17e7-f1dc-4c7f-83bd-5f8e0c3c227a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_d28d7dd3-cfe7-4a94-8519-883280c39dbc" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_0f2768d7-772e-4ae9-8564-962600557d68" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_d28d7dd3-cfe7-4a94-8519-883280c39dbc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_d28d7dd3-cfe7-4a94-8519-883280c39dbc_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_d28d7dd3-cfe7-4a94-8519-883280c39dbc" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_d28d7dd3-cfe7-4a94-8519-883280c39dbc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_2a269cb9-3dcc-476d-a141-e480dedd60c5" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_d28d7dd3-cfe7-4a94-8519-883280c39dbc" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_2a269cb9-3dcc-476d-a141-e480dedd60c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_7d3d86c4-725d-4b86-8275-090eef457cc5" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_2a269cb9-3dcc-476d-a141-e480dedd60c5" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_7d3d86c4-725d-4b86-8275-090eef457cc5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/ReportableBusinessSegmentsSegmentDataDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#ReportableBusinessSegmentsSegmentDataDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/ReportableBusinessSegmentsSegmentDataDetails" xlink:type="extended" id="ic9b2787f4dac447c890a6afa6495296c_ReportableBusinessSegmentsSegmentDataDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_b8736081-bab1-4e69-9c05-a0683977cc26" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_ffe050c5-6254-49c6-a907-7f61a8ef86c3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_b8736081-bab1-4e69-9c05-a0683977cc26" xlink:to="loc_us-gaap_NumberOfReportableSegments_ffe050c5-6254-49c6-a907-7f61a8ef86c3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract_0b8c0d3d-f135-4a66-9b48-4041ca2bb66b" xlink:href="lii-20210930.xsd#lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_b8736081-bab1-4e69-9c05-a0683977cc26" xlink:to="loc_lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract_0b8c0d3d-f135-4a66-9b48-4041ca2bb66b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_4169cbbb-c718-4ade-b779-50e3812cd8cb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract_0b8c0d3d-f135-4a66-9b48-4041ca2bb66b" xlink:to="loc_us-gaap_RevenuesAbstract_4169cbbb-c718-4ade-b779-50e3812cd8cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_7f4c8982-df84-4d07-9af2-02eaa9958ff5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_4169cbbb-c718-4ade-b779-50e3812cd8cb" xlink:to="loc_us-gaap_Revenues_7f4c8982-df84-4d07-9af2-02eaa9958ff5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationProfitLossAbstract_d794ca55-1290-478e-b7b3-f5ffd807a0fd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentReportingInformationProfitLossAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract_0b8c0d3d-f135-4a66-9b48-4041ca2bb66b" xlink:to="loc_us-gaap_SegmentReportingInformationProfitLossAbstract_d794ca55-1290-478e-b7b3-f5ffd807a0fd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_SegmentProfitAndLoss_0feee55a-8ac2-4a9f-8ced-62596445a0ba" xlink:href="lii-20210930.xsd#lii_SegmentProfitAndLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationProfitLossAbstract_d794ca55-1290-478e-b7b3-f5ffd807a0fd" xlink:to="loc_lii_SegmentProfitAndLoss_0feee55a-8ac2-4a9f-8ced-62596445a0ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_fd6f8d82-e757-42af-8e56-c5eddfc883d9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract_0b8c0d3d-f135-4a66-9b48-4041ca2bb66b" xlink:to="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_fd6f8d82-e757-42af-8e56-c5eddfc883d9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_NetLossgainfromnaturaldisaster_a6bb9f80-c8f7-4bf5-951e-41c927ca39df" xlink:href="lii-20210930.xsd#lii_NetLossgainfromnaturaldisaster"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_fd6f8d82-e757-42af-8e56-c5eddfc883d9" xlink:to="loc_lii_NetLossgainfromnaturaldisaster_a6bb9f80-c8f7-4bf5-951e-41c927ca39df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_LossgainfromnaturaldisasternetofInsurancerecoveries_d28c205b-ecde-4b76-aad2-c8cf93b73a13" xlink:href="lii-20210930.xsd#lii_LossgainfromnaturaldisasternetofInsurancerecoveries"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_fd6f8d82-e757-42af-8e56-c5eddfc883d9" xlink:to="loc_lii_LossgainfromnaturaldisasternetofInsurancerecoveries_d28c205b-ecde-4b76-aad2-c8cf93b73a13" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_SegmentReportingReconcilingItemInLossesAndOtherExpensesFromSegmentToConsolidatedAmount_c4a1fb2d-c776-4316-9428-b9b47d853cc1" xlink:href="lii-20210930.xsd#lii_SegmentReportingReconcilingItemInLossesAndOtherExpensesFromSegmentToConsolidatedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_fd6f8d82-e757-42af-8e56-c5eddfc883d9" xlink:to="loc_lii_SegmentReportingReconcilingItemInLossesAndOtherExpensesFromSegmentToConsolidatedAmount_c4a1fb2d-c776-4316-9428-b9b47d853cc1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_f83e37e2-749a-47e1-a030-d87d61cac273" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_fd6f8d82-e757-42af-8e56-c5eddfc883d9" xlink:to="loc_us-gaap_RestructuringCharges_f83e37e2-749a-47e1-a030-d87d61cac273" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_f17d735b-6450-48d4-8aab-2a69e4299a23" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_fd6f8d82-e757-42af-8e56-c5eddfc883d9" xlink:to="loc_us-gaap_OperatingIncomeLoss_f17d735b-6450-48d4-8aab-2a69e4299a23" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_9e322e4f-ada3-452f-a06e-b7380547aea3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_b8736081-bab1-4e69-9c05-a0683977cc26" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_9e322e4f-ada3-452f-a06e-b7380547aea3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_Specialinventorywritedown_5746623c-7a8e-4f67-b743-a023f0a31045" xlink:href="lii-20210930.xsd#lii_Specialinventorywritedown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_b8736081-bab1-4e69-9c05-a0683977cc26" xlink:to="loc_lii_Specialinventorywritedown_5746623c-7a8e-4f67-b743-a023f0a31045" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_a7a47c33-f312-4039-8b44-ddf6b51efd20" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_b8736081-bab1-4e69-9c05-a0683977cc26" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_a7a47c33-f312-4039-8b44-ddf6b51efd20" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_c1ce4a80-e835-4b26-9bc6-74588622ff10" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_a7a47c33-f312-4039-8b44-ddf6b51efd20" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_c1ce4a80-e835-4b26-9bc6-74588622ff10" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_c1ce4a80-e835-4b26-9bc6-74588622ff10_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_c1ce4a80-e835-4b26-9bc6-74588622ff10" xlink:to="loc_us-gaap_SegmentDomain_c1ce4a80-e835-4b26-9bc6-74588622ff10_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_9c9b80f0-ef36-42ea-9a0c-0dbffe9dc3f4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_c1ce4a80-e835-4b26-9bc6-74588622ff10" xlink:to="loc_us-gaap_SegmentDomain_9c9b80f0-ef36-42ea-9a0c-0dbffe9dc3f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ResidentialHeatingAndCoolingMember_ca5093be-ae50-4273-a5dd-7e0489eb530c" xlink:href="lii-20210930.xsd#lii_ResidentialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9c9b80f0-ef36-42ea-9a0c-0dbffe9dc3f4" xlink:to="loc_lii_ResidentialHeatingAndCoolingMember_ca5093be-ae50-4273-a5dd-7e0489eb530c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_31812164-39ba-439d-ace2-d0a81d32acec" xlink:href="lii-20210930.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9c9b80f0-ef36-42ea-9a0c-0dbffe9dc3f4" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_31812164-39ba-439d-ace2-d0a81d32acec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_RefrigerationMember_8c25e1c0-3fa6-4394-bbb3-004b46d7bdbe" xlink:href="lii-20210930.xsd#lii_RefrigerationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9c9b80f0-ef36-42ea-9a0c-0dbffe9dc3f4" xlink:to="loc_lii_RefrigerationMember_8c25e1c0-3fa6-4394-bbb3-004b46d7bdbe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateAndOtherMember_01ba4b6a-0e9d-4592-bed6-69aa57c34bde" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CorporateAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9c9b80f0-ef36-42ea-9a0c-0dbffe9dc3f4" xlink:to="loc_us-gaap_CorporateAndOtherMember_01ba4b6a-0e9d-4592-bed6-69aa57c34bde" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_abe40e8b-d786-4a1a-93d0-ed1121cfbcbd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_a7a47c33-f312-4039-8b44-ddf6b51efd20" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_abe40e8b-d786-4a1a-93d0-ed1121cfbcbd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_abe40e8b-d786-4a1a-93d0-ed1121cfbcbd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_abe40e8b-d786-4a1a-93d0-ed1121cfbcbd" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_abe40e8b-d786-4a1a-93d0-ed1121cfbcbd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_588cfca0-85e5-42ba-b84a-adebcf3c8c65" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_abe40e8b-d786-4a1a-93d0-ed1121cfbcbd" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_588cfca0-85e5-42ba-b84a-adebcf3c8c65" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelDirectlyToConsumerMember_66d36906-b044-4fc9-9cd4-22631940d03b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SalesChannelDirectlyToConsumerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_588cfca0-85e5-42ba-b84a-adebcf3c8c65" xlink:to="loc_us-gaap_SalesChannelDirectlyToConsumerMember_66d36906-b044-4fc9-9cd4-22631940d03b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_3b78fa3f-6156-4670-9879-3f4beccb21c1" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_a7a47c33-f312-4039-8b44-ddf6b51efd20" xlink:to="loc_srt_ProductOrServiceAxis_3b78fa3f-6156-4670-9879-3f4beccb21c1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_3b78fa3f-6156-4670-9879-3f4beccb21c1_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_3b78fa3f-6156-4670-9879-3f4beccb21c1" xlink:to="loc_srt_ProductsAndServicesDomain_3b78fa3f-6156-4670-9879-3f4beccb21c1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_ab286811-e2a2-4686-8aec-a48d0407f134" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_3b78fa3f-6156-4670-9879-3f4beccb21c1" xlink:to="loc_srt_ProductsAndServicesDomain_ab286811-e2a2-4686-8aec-a48d0407f134" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_EquipmentSalesMember_c3cde3b5-4093-4aa5-a63a-9053672ed4cb" xlink:href="lii-20210930.xsd#lii_EquipmentSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_ab286811-e2a2-4686-8aec-a48d0407f134" xlink:to="loc_lii_EquipmentSalesMember_c3cde3b5-4093-4aa5-a63a-9053672ed4cb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ServiceRevenueMember_5fb3e121-587e-49bb-88fa-c150279a7ed6" xlink:href="lii-20210930.xsd#lii_ServiceRevenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_ab286811-e2a2-4686-8aec-a48d0407f134" xlink:to="loc_lii_ServiceRevenueMember_5fb3e121-587e-49bb-88fa-c150279a7ed6" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/EarningsPerShareExcludedfromDilutedEarningsPerShareCalculationDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#EarningsPerShareExcludedfromDilutedEarningsPerShareCalculationDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/EarningsPerShareExcludedfromDilutedEarningsPerShareCalculationDetails" xlink:type="extended" id="i61d9fda3e09a4049b8fc7ebda91d3e3c_EarningsPerShareExcludedfromDilutedEarningsPerShareCalculationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_5b322a30-50b3-44d0-b6a2-ec0fd8c32dd4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_39283699-3036-49b0-8ee6-25eac875b5c2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_5b322a30-50b3-44d0-b6a2-ec0fd8c32dd4" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_39283699-3036-49b0-8ee6-25eac875b5c2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfNetIncomePerOutstandingUnitAmount_c8e2b4a4-08c5-4cf6-a368-e1d3059ae05c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfNetIncomePerOutstandingUnitAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_5b322a30-50b3-44d0-b6a2-ec0fd8c32dd4" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfNetIncomePerOutstandingUnitAmount_c8e2b4a4-08c5-4cf6-a368-e1d3059ae05c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_70cdc318-8386-4742-bb53-890bb84e14df" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_5b322a30-50b3-44d0-b6a2-ec0fd8c32dd4" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_70cdc318-8386-4742-bb53-890bb84e14df" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_31664626-3931-4456-af21-03332dbb2d9e" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_70cdc318-8386-4742-bb53-890bb84e14df" xlink:to="loc_srt_RangeAxis_31664626-3931-4456-af21-03332dbb2d9e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_31664626-3931-4456-af21-03332dbb2d9e_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_31664626-3931-4456-af21-03332dbb2d9e" xlink:to="loc_srt_RangeMember_31664626-3931-4456-af21-03332dbb2d9e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2a8a3e93-523a-41e9-80a4-b9ec165e3553" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_31664626-3931-4456-af21-03332dbb2d9e" xlink:to="loc_srt_RangeMember_2a8a3e93-523a-41e9-80a4-b9ec165e3553" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_4c75d90b-d897-4c8d-b375-1c97f9c1ffee" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2a8a3e93-523a-41e9-80a4-b9ec165e3553" xlink:to="loc_srt_MinimumMember_4c75d90b-d897-4c8d-b375-1c97f9c1ffee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_96105b91-1384-47f7-ab24-a396a5865eac" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2a8a3e93-523a-41e9-80a4-b9ec165e3553" xlink:to="loc_srt_MaximumMember_96105b91-1384-47f7-ab24-a396a5865eac" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/CommitmentsandContingenciesChangesinProductWarrantyLiabilitiesDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#CommitmentsandContingenciesChangesinProductWarrantyLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/CommitmentsandContingenciesChangesinProductWarrantyLiabilitiesDetails" xlink:type="extended" id="i871396f7a1cb4e5d873b3d99622f5e9e_CommitmentsandContingenciesChangesinProductWarrantyLiabilitiesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_7c263ace-09df-49cd-b1a4-6a7ad8737eb0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_3ef58ef0-7a75-4afa-8d83-bc3f2a1ab05b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_7c263ace-09df-49cd-b1a4-6a7ad8737eb0" xlink:to="loc_us-gaap_LossContingenciesTable_3ef58ef0-7a75-4afa-8d83-bc3f2a1ab05b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_fbc750fb-3894-4fdd-9582-a996e7b99351" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_3ef58ef0-7a75-4afa-8d83-bc3f2a1ab05b" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_fbc750fb-3894-4fdd-9582-a996e7b99351" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_fbc750fb-3894-4fdd-9582-a996e7b99351_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_fbc750fb-3894-4fdd-9582-a996e7b99351" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_fbc750fb-3894-4fdd-9582-a996e7b99351_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_5d480b9c-618f-4d89-b6d1-857d84811a36" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_fbc750fb-3894-4fdd-9582-a996e7b99351" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_5d480b9c-618f-4d89-b6d1-857d84811a36" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_8fee4924-99d5-4f4b-99a6-a6f5c6855893" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_3ef58ef0-7a75-4afa-8d83-bc3f2a1ab05b" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_8fee4924-99d5-4f4b-99a6-a6f5c6855893" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_8fee4924-99d5-4f4b-99a6-a6f5c6855893_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_8fee4924-99d5-4f4b-99a6-a6f5c6855893" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_8fee4924-99d5-4f4b-99a6-a6f5c6855893_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_90361396-bb3b-4c0b-9044-3cd5d98fd94f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_8fee4924-99d5-4f4b-99a6-a6f5c6855893" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_90361396-bb3b-4c0b-9044-3cd5d98fd94f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_7fecad99-2e15-4668-a025-f1b5719a3789" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_LitigationCaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_3ef58ef0-7a75-4afa-8d83-bc3f2a1ab05b" xlink:to="loc_srt_LitigationCaseAxis_7fecad99-2e15-4668-a025-f1b5719a3789" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_7fecad99-2e15-4668-a025-f1b5719a3789_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_7fecad99-2e15-4668-a025-f1b5719a3789" xlink:to="loc_srt_LitigationCaseTypeDomain_7fecad99-2e15-4668-a025-f1b5719a3789_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_46b21d6d-2693-45bd-a94e-c95099500089" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_7fecad99-2e15-4668-a025-f1b5719a3789" xlink:to="loc_srt_LitigationCaseTypeDomain_46b21d6d-2693-45bd-a94e-c95099500089" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusAxis_b5b5b2a6-33ac-46a1-83f2-ce18e3bb854c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LitigationStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_3ef58ef0-7a75-4afa-8d83-bc3f2a1ab05b" xlink:to="loc_us-gaap_LitigationStatusAxis_b5b5b2a6-33ac-46a1-83f2-ce18e3bb854c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_b5b5b2a6-33ac-46a1-83f2-ce18e3bb854c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LitigationStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LitigationStatusAxis_b5b5b2a6-33ac-46a1-83f2-ce18e3bb854c" xlink:to="loc_us-gaap_LitigationStatusDomain_b5b5b2a6-33ac-46a1-83f2-ce18e3bb854c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_0f65a10b-133e-4659-9d92-034f1d9b98d5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LitigationStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LitigationStatusAxis_b5b5b2a6-33ac-46a1-83f2-ce18e3bb854c" xlink:to="loc_us-gaap_LitigationStatusDomain_0f65a10b-133e-4659-9d92-034f1d9b98d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_3c5c7d8a-bcb4-4567-98fc-69a2679ccc71" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_3ef58ef0-7a75-4afa-8d83-bc3f2a1ab05b" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_3c5c7d8a-bcb4-4567-98fc-69a2679ccc71" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_3c5c7d8a-bcb4-4567-98fc-69a2679ccc71_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_3c5c7d8a-bcb4-4567-98fc-69a2679ccc71" xlink:to="loc_us-gaap_LossContingencyNatureDomain_3c5c7d8a-bcb4-4567-98fc-69a2679ccc71_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_efe50511-2cf9-4e68-ae51-a6fcc72be64e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_3c5c7d8a-bcb4-4567-98fc-69a2679ccc71" xlink:to="loc_us-gaap_LossContingencyNatureDomain_efe50511-2cf9-4e68-ae51-a6fcc72be64e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_1ed16b8e-8f0c-4546-af75-3891ac85703b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_3ef58ef0-7a75-4afa-8d83-bc3f2a1ab05b" xlink:to="loc_srt_RangeAxis_1ed16b8e-8f0c-4546-af75-3891ac85703b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_1ed16b8e-8f0c-4546-af75-3891ac85703b_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_1ed16b8e-8f0c-4546-af75-3891ac85703b" xlink:to="loc_srt_RangeMember_1ed16b8e-8f0c-4546-af75-3891ac85703b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2a7cca2f-60f2-430c-b829-3a85d1a4f472" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_1ed16b8e-8f0c-4546-af75-3891ac85703b" xlink:to="loc_srt_RangeMember_2a7cca2f-60f2-430c-b829-3a85d1a4f472" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/CommitmentsandContingenciesNarrativeDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#CommitmentsandContingenciesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/CommitmentsandContingenciesNarrativeDetails" xlink:type="extended" id="iaa90428433084230b2af957c06f9c2ad_CommitmentsandContingenciesNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_598e87b6-9411-4ff8-b1c1-b80d71f9462a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_58e978f4-4cc8-4e2c-b1b8-b54b0a96517c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_598e87b6-9411-4ff8-b1c1-b80d71f9462a" xlink:to="loc_us-gaap_LossContingenciesTable_58e978f4-4cc8-4e2c-b1b8-b54b0a96517c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_3e472f63-c4b6-4d63-adc0-eda3ef48a599" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_58e978f4-4cc8-4e2c-b1b8-b54b0a96517c" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_3e472f63-c4b6-4d63-adc0-eda3ef48a599" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_3e472f63-c4b6-4d63-adc0-eda3ef48a599_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_3e472f63-c4b6-4d63-adc0-eda3ef48a599" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_3e472f63-c4b6-4d63-adc0-eda3ef48a599_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_281d579c-4380-4cee-88f9-c384f24d96be" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_3e472f63-c4b6-4d63-adc0-eda3ef48a599" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_281d579c-4380-4cee-88f9-c384f24d96be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_ab500e3f-5ab7-48dc-a09a-b2f0ba41faa2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_58e978f4-4cc8-4e2c-b1b8-b54b0a96517c" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_ab500e3f-5ab7-48dc-a09a-b2f0ba41faa2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_ab500e3f-5ab7-48dc-a09a-b2f0ba41faa2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_ab500e3f-5ab7-48dc-a09a-b2f0ba41faa2" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_ab500e3f-5ab7-48dc-a09a-b2f0ba41faa2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_7eb0e269-712b-4492-ae4b-219e2a87d265" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_ab500e3f-5ab7-48dc-a09a-b2f0ba41faa2" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_7eb0e269-712b-4492-ae4b-219e2a87d265" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_06c906ff-6dbc-4a5e-8bac-3c0a43f3a9ee" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_LitigationCaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_58e978f4-4cc8-4e2c-b1b8-b54b0a96517c" xlink:to="loc_srt_LitigationCaseAxis_06c906ff-6dbc-4a5e-8bac-3c0a43f3a9ee" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_06c906ff-6dbc-4a5e-8bac-3c0a43f3a9ee_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_06c906ff-6dbc-4a5e-8bac-3c0a43f3a9ee" xlink:to="loc_srt_LitigationCaseTypeDomain_06c906ff-6dbc-4a5e-8bac-3c0a43f3a9ee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_2a412e07-e417-419d-8c46-f429075bb563" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_06c906ff-6dbc-4a5e-8bac-3c0a43f3a9ee" xlink:to="loc_srt_LitigationCaseTypeDomain_2a412e07-e417-419d-8c46-f429075bb563" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusAxis_36421d17-3408-49e1-b377-5e4f59ba2641" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LitigationStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_58e978f4-4cc8-4e2c-b1b8-b54b0a96517c" xlink:to="loc_us-gaap_LitigationStatusAxis_36421d17-3408-49e1-b377-5e4f59ba2641" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_36421d17-3408-49e1-b377-5e4f59ba2641_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LitigationStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LitigationStatusAxis_36421d17-3408-49e1-b377-5e4f59ba2641" xlink:to="loc_us-gaap_LitigationStatusDomain_36421d17-3408-49e1-b377-5e4f59ba2641_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_ece199f4-108f-4d5d-9ac8-ff8ac78f16df" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LitigationStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LitigationStatusAxis_36421d17-3408-49e1-b377-5e4f59ba2641" xlink:to="loc_us-gaap_LitigationStatusDomain_ece199f4-108f-4d5d-9ac8-ff8ac78f16df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_ffae42a6-253d-4044-b477-9cc0dda53573" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_58e978f4-4cc8-4e2c-b1b8-b54b0a96517c" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_ffae42a6-253d-4044-b477-9cc0dda53573" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_ffae42a6-253d-4044-b477-9cc0dda53573_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_ffae42a6-253d-4044-b477-9cc0dda53573" xlink:to="loc_us-gaap_LossContingencyNatureDomain_ffae42a6-253d-4044-b477-9cc0dda53573_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_d5f232be-f4cf-40da-9733-a025e8b722c7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_ffae42a6-253d-4044-b477-9cc0dda53573" xlink:to="loc_us-gaap_LossContingencyNatureDomain_d5f232be-f4cf-40da-9733-a025e8b722c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_ab95cad9-6e01-456f-97ad-b5faaf9080ff" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_58e978f4-4cc8-4e2c-b1b8-b54b0a96517c" xlink:to="loc_srt_RangeAxis_ab95cad9-6e01-456f-97ad-b5faaf9080ff" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_ab95cad9-6e01-456f-97ad-b5faaf9080ff_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_ab95cad9-6e01-456f-97ad-b5faaf9080ff" xlink:to="loc_srt_RangeMember_ab95cad9-6e01-456f-97ad-b5faaf9080ff_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_be1e8218-e55f-427d-9134-a358e003e985" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_ab95cad9-6e01-456f-97ad-b5faaf9080ff" xlink:to="loc_srt_RangeMember_be1e8218-e55f-427d-9134-a358e003e985" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/StockRepurchasesDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#StockRepurchasesDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/StockRepurchasesDetails" xlink:type="extended" id="ib8438810dc614779885d3653613f6c48_StockRepurchasesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_aababb11-7e51-46fd-87a6-878d6aa87415" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_f439ab3a-6ef3-4e66-8337-3394808e3d43" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_aababb11-7e51-46fd-87a6-878d6aa87415" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_f439ab3a-6ef3-4e66-8337-3394808e3d43" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_PercentageOfAcceleratedShareRepurchasesOfSharesExpectedToBeRepurchased_59906b6a-8bf7-497a-a5bd-ae04c530cae5" xlink:href="lii-20210930.xsd#lii_PercentageOfAcceleratedShareRepurchasesOfSharesExpectedToBeRepurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_aababb11-7e51-46fd-87a6-878d6aa87415" xlink:to="loc_lii_PercentageOfAcceleratedShareRepurchasesOfSharesExpectedToBeRepurchased_59906b6a-8bf7-497a-a5bd-ae04c530cae5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_c50a6d71-d36b-47c8-9108-c5dc8bd6a2fd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_aababb11-7e51-46fd-87a6-878d6aa87415" xlink:to="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_c50a6d71-d36b-47c8-9108-c5dc8bd6a2fd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_b6016405-fbb3-4a5e-8a99-36ad1dad4ac6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_aababb11-7e51-46fd-87a6-878d6aa87415" xlink:to="loc_us-gaap_StatementTable_b6016405-fbb3-4a5e-8a99-36ad1dad4ac6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RestatementAxis_f3b2019d-5b7e-4b36-8bf0-50a798ad54e3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RestatementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_b6016405-fbb3-4a5e-8a99-36ad1dad4ac6" xlink:to="loc_srt_RestatementAxis_f3b2019d-5b7e-4b36-8bf0-50a798ad54e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RestatementDomain_f3b2019d-5b7e-4b36-8bf0-50a798ad54e3_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RestatementDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RestatementAxis_f3b2019d-5b7e-4b36-8bf0-50a798ad54e3" xlink:to="loc_srt_RestatementDomain_f3b2019d-5b7e-4b36-8bf0-50a798ad54e3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RestatementDomain_0e423e10-c340-4814-9e82-30fe747f1e38" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RestatementDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RestatementAxis_f3b2019d-5b7e-4b36-8bf0-50a798ad54e3" xlink:to="loc_srt_RestatementDomain_0e423e10-c340-4814-9e82-30fe747f1e38" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_29679e73-1da0-407f-9298-ffc7cb3c59f3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_b6016405-fbb3-4a5e-8a99-36ad1dad4ac6" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_29679e73-1da0-407f-9298-ffc7cb3c59f3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_29679e73-1da0-407f-9298-ffc7cb3c59f3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_29679e73-1da0-407f-9298-ffc7cb3c59f3" xlink:to="loc_us-gaap_EquityComponentDomain_29679e73-1da0-407f-9298-ffc7cb3c59f3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_79c3a902-40fd-46ea-8b91-45fa55de0ffe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_29679e73-1da0-407f-9298-ffc7cb3c59f3" xlink:to="loc_us-gaap_EquityComponentDomain_79c3a902-40fd-46ea-8b91-45fa55de0ffe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_e6a343bc-4dc5-42ea-9abd-7ef24a557f71" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_b6016405-fbb3-4a5e-8a99-36ad1dad4ac6" xlink:to="loc_us-gaap_StatementClassOfStockAxis_e6a343bc-4dc5-42ea-9abd-7ef24a557f71" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_e6a343bc-4dc5-42ea-9abd-7ef24a557f71_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_e6a343bc-4dc5-42ea-9abd-7ef24a557f71" xlink:to="loc_us-gaap_ClassOfStockDomain_e6a343bc-4dc5-42ea-9abd-7ef24a557f71_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_a90f4112-fdb5-4952-bbfa-2722f8a61452" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_e6a343bc-4dc5-42ea-9abd-7ef24a557f71" xlink:to="loc_us-gaap_ClassOfStockDomain_a90f4112-fdb5-4952-bbfa-2722f8a61452" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_dfea4c4f-8d25-4d9d-a55b-252cf8a014f4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_b6016405-fbb3-4a5e-8a99-36ad1dad4ac6" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_dfea4c4f-8d25-4d9d-a55b-252cf8a014f4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_dfea4c4f-8d25-4d9d-a55b-252cf8a014f4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_dfea4c4f-8d25-4d9d-a55b-252cf8a014f4" xlink:to="loc_us-gaap_TypeOfAdoptionMember_dfea4c4f-8d25-4d9d-a55b-252cf8a014f4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_876dde3d-5fdb-4c84-9b04-5074f1a2f851" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_dfea4c4f-8d25-4d9d-a55b-252cf8a014f4" xlink:to="loc_us-gaap_TypeOfAdoptionMember_876dde3d-5fdb-4c84-9b04-5074f1a2f851" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis_769403fa-762d-4116-9a20-0f825fdd3b65" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_b6016405-fbb3-4a5e-8a99-36ad1dad4ac6" xlink:to="loc_us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis_769403fa-762d-4116-9a20-0f825fdd3b65" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInAccountingPrincipleMember_769403fa-762d-4116-9a20-0f825fdd3b65_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ChangeInAccountingPrincipleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis_769403fa-762d-4116-9a20-0f825fdd3b65" xlink:to="loc_us-gaap_ChangeInAccountingPrincipleMember_769403fa-762d-4116-9a20-0f825fdd3b65_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInAccountingPrincipleMember_9d18f17a-97fd-41a6-b15d-12d9a085ed08" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ChangeInAccountingPrincipleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis_769403fa-762d-4116-9a20-0f825fdd3b65" xlink:to="loc_us-gaap_ChangeInAccountingPrincipleMember_9d18f17a-97fd-41a6-b15d-12d9a085ed08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis_9ee5a962-3e4d-4049-9132-f776166e45e3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_b6016405-fbb3-4a5e-8a99-36ad1dad4ac6" xlink:to="loc_us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis_9ee5a962-3e4d-4049-9132-f776166e45e3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForErrorCorrectionDomain_9ee5a962-3e4d-4049-9132-f776166e45e3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsForErrorCorrectionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis_9ee5a962-3e4d-4049-9132-f776166e45e3" xlink:to="loc_us-gaap_AdjustmentsForErrorCorrectionDomain_9ee5a962-3e4d-4049-9132-f776166e45e3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForErrorCorrectionDomain_ac9568ae-e986-4679-85b6-05e97d7978bc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsForErrorCorrectionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementByRestatementPeriodAndAmountAxis_9ee5a962-3e4d-4049-9132-f776166e45e3" xlink:to="loc_us-gaap_AdjustmentsForErrorCorrectionDomain_ac9568ae-e986-4679-85b6-05e97d7978bc" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/RevenueRecognitionNarrativeDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#RevenueRecognitionNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/RevenueRecognitionNarrativeDetails" xlink:type="extended" id="i4319b1baa8e145d7a5bf8f27c09cbc91_RevenueRecognitionNarrativeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_a1fc5e8b-600d-4fbd-9a6d-633a6db38aa7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_fe1cb114-53b8-4d93-9491-e45889cfccdb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_a1fc5e8b-600d-4fbd-9a6d-633a6db38aa7" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_fe1cb114-53b8-4d93-9491-e45889cfccdb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_a345fe7a-3592-4a08-96d3-2cc658f10862" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_a1fc5e8b-600d-4fbd-9a6d-633a6db38aa7" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_a345fe7a-3592-4a08-96d3-2cc658f10862" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_ea29e29a-a200-45ab-be11-737570a600e5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_a1fc5e8b-600d-4fbd-9a6d-633a6db38aa7" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_ea29e29a-a200-45ab-be11-737570a600e5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_dc472f08-67c2-4b2e-a072-76a6d044356e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_ea29e29a-a200-45ab-be11-737570a600e5" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_dc472f08-67c2-4b2e-a072-76a6d044356e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_dc472f08-67c2-4b2e-a072-76a6d044356e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_dc472f08-67c2-4b2e-a072-76a6d044356e" xlink:to="loc_us-gaap_SegmentDomain_dc472f08-67c2-4b2e-a072-76a6d044356e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_f8b7431c-06a6-4e77-aafd-31573855afba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_dc472f08-67c2-4b2e-a072-76a6d044356e" xlink:to="loc_us-gaap_SegmentDomain_f8b7431c-06a6-4e77-aafd-31573855afba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_RefrigerationMember_9a2442c3-8922-40aa-bf01-463b7934f533" xlink:href="lii-20210930.xsd#lii_RefrigerationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_f8b7431c-06a6-4e77-aafd-31573855afba" xlink:to="loc_lii_RefrigerationMember_9a2442c3-8922-40aa-bf01-463b7934f533" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ResidentialHeatingAndCoolingMember_ea8fd006-0c50-46a6-b506-0352c42d4601" xlink:href="lii-20210930.xsd#lii_ResidentialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_f8b7431c-06a6-4e77-aafd-31573855afba" xlink:to="loc_lii_ResidentialHeatingAndCoolingMember_ea8fd006-0c50-46a6-b506-0352c42d4601" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_4ec8fd28-bfa9-4762-b798-78c5a54756a0" xlink:href="lii-20210930.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_f8b7431c-06a6-4e77-aafd-31573855afba" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_4ec8fd28-bfa9-4762-b798-78c5a54756a0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_c2bb18d2-c395-430d-9917-44ea95e7f583" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_ea29e29a-a200-45ab-be11-737570a600e5" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_c2bb18d2-c395-430d-9917-44ea95e7f583" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_c2bb18d2-c395-430d-9917-44ea95e7f583_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_c2bb18d2-c395-430d-9917-44ea95e7f583" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_c2bb18d2-c395-430d-9917-44ea95e7f583_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_cf5de872-ef94-415f-9e71-019bb848c7c4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_c2bb18d2-c395-430d-9917-44ea95e7f583" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_cf5de872-ef94-415f-9e71-019bb848c7c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelDirectlyToConsumerMember_edaa2d75-743e-4fa8-87ff-c12a8a954e57" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SalesChannelDirectlyToConsumerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_cf5de872-ef94-415f-9e71-019bb848c7c4" xlink:to="loc_us-gaap_SalesChannelDirectlyToConsumerMember_edaa2d75-743e-4fa8-87ff-c12a8a954e57" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_6a1a584e-248d-49d4-bc5b-95b8d6bd6cf2" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_ea29e29a-a200-45ab-be11-737570a600e5" xlink:to="loc_srt_ProductOrServiceAxis_6a1a584e-248d-49d4-bc5b-95b8d6bd6cf2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_6a1a584e-248d-49d4-bc5b-95b8d6bd6cf2_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_6a1a584e-248d-49d4-bc5b-95b8d6bd6cf2" xlink:to="loc_srt_ProductsAndServicesDomain_6a1a584e-248d-49d4-bc5b-95b8d6bd6cf2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_a215e11c-c1e7-4708-b111-1ae376f37b42" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_6a1a584e-248d-49d4-bc5b-95b8d6bd6cf2" xlink:to="loc_srt_ProductsAndServicesDomain_a215e11c-c1e7-4708-b111-1ae376f37b42" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_EquipmentSalesMember_95740983-95a4-4f7e-a1dc-53a06ef331c3" xlink:href="lii-20210930.xsd#lii_EquipmentSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_a215e11c-c1e7-4708-b111-1ae376f37b42" xlink:to="loc_lii_EquipmentSalesMember_95740983-95a4-4f7e-a1dc-53a06ef331c3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_1ef3152d-8ffc-4a0b-9cef-326568296687" xlink:href="lii-20210930.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_a215e11c-c1e7-4708-b111-1ae376f37b42" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_1ef3152d-8ffc-4a0b-9cef-326568296687" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/RevenueRecognitionRevenuebyBusinessSegmentbyGeographyDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#RevenueRecognitionRevenuebyBusinessSegmentbyGeographyDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/RevenueRecognitionRevenuebyBusinessSegmentbyGeographyDetails" xlink:type="extended" id="i2e01c5b0db4b4bd2a6d8b05266683f69_RevenueRecognitionRevenuebyBusinessSegmentbyGeographyDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_1bbed01b-b3d1-4f9e-911e-93e38e9ae87d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_97b3081b-87cc-4f72-b06b-daa72e615f8a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_1bbed01b-b3d1-4f9e-911e-93e38e9ae87d" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_97b3081b-87cc-4f72-b06b-daa72e615f8a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_48202031-2681-4d51-891e-ae6fe4fc452e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_1bbed01b-b3d1-4f9e-911e-93e38e9ae87d" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_48202031-2681-4d51-891e-ae6fe4fc452e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_e4d17f2f-8765-47e6-803d-97e2ba57dc7a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_1bbed01b-b3d1-4f9e-911e-93e38e9ae87d" xlink:to="loc_us-gaap_Revenues_e4d17f2f-8765-47e6-803d-97e2ba57dc7a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_a3a5a77b-0d3f-463b-8ba8-cc3ab9d7a5bf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_1bbed01b-b3d1-4f9e-911e-93e38e9ae87d" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_a3a5a77b-0d3f-463b-8ba8-cc3ab9d7a5bf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicDistributionAxis_6b621e30-9ae7-454e-98a6-2495e4f54578" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeographicDistributionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_a3a5a77b-0d3f-463b-8ba8-cc3ab9d7a5bf" xlink:to="loc_us-gaap_GeographicDistributionAxis_6b621e30-9ae7-454e-98a6-2495e4f54578" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicDistributionDomain_6b621e30-9ae7-454e-98a6-2495e4f54578_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeographicDistributionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GeographicDistributionAxis_6b621e30-9ae7-454e-98a6-2495e4f54578" xlink:to="loc_us-gaap_GeographicDistributionDomain_6b621e30-9ae7-454e-98a6-2495e4f54578_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicDistributionDomain_e13966c2-5357-4d03-8a0d-841b04d3e9c9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeographicDistributionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GeographicDistributionAxis_6b621e30-9ae7-454e-98a6-2495e4f54578" xlink:to="loc_us-gaap_GeographicDistributionDomain_e13966c2-5357-4d03-8a0d-841b04d3e9c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_InternationalMember_c47d04d6-9de1-49e7-a3a1-93403ef6cae5" xlink:href="lii-20210930.xsd#lii_InternationalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GeographicDistributionDomain_e13966c2-5357-4d03-8a0d-841b04d3e9c9" xlink:to="loc_lii_InternationalMember_c47d04d6-9de1-49e7-a3a1-93403ef6cae5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_CA_f4e17e8c-aef2-4bae-b86f-5c2ea6db5a0b" xlink:href="https://xbrl.sec.gov/country/2021/country-2021.xsd#country_CA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GeographicDistributionDomain_e13966c2-5357-4d03-8a0d-841b04d3e9c9" xlink:to="loc_country_CA_f4e17e8c-aef2-4bae-b86f-5c2ea6db5a0b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_2bed5886-476f-4980-9330-9e91879cc204" xlink:href="https://xbrl.sec.gov/country/2021/country-2021.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GeographicDistributionDomain_e13966c2-5357-4d03-8a0d-841b04d3e9c9" xlink:to="loc_country_US_2bed5886-476f-4980-9330-9e91879cc204" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_3fedaac9-b727-4a7c-aeb8-0717db1a93e6" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_a3a5a77b-0d3f-463b-8ba8-cc3ab9d7a5bf" xlink:to="loc_srt_ProductOrServiceAxis_3fedaac9-b727-4a7c-aeb8-0717db1a93e6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_3fedaac9-b727-4a7c-aeb8-0717db1a93e6_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_3fedaac9-b727-4a7c-aeb8-0717db1a93e6" xlink:to="loc_srt_ProductsAndServicesDomain_3fedaac9-b727-4a7c-aeb8-0717db1a93e6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_086bf18e-05c6-4988-a36e-7e3cfa9b3270" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_3fedaac9-b727-4a7c-aeb8-0717db1a93e6" xlink:to="loc_srt_ProductsAndServicesDomain_086bf18e-05c6-4988-a36e-7e3cfa9b3270" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_EquipmentSalesMember_55e9c5b3-aa6b-4434-a4f8-6e265abf092a" xlink:href="lii-20210930.xsd#lii_EquipmentSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_086bf18e-05c6-4988-a36e-7e3cfa9b3270" xlink:to="loc_lii_EquipmentSalesMember_55e9c5b3-aa6b-4434-a4f8-6e265abf092a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_72eb92bb-63f8-4b07-a124-538e751321a6" xlink:href="lii-20210930.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_086bf18e-05c6-4988-a36e-7e3cfa9b3270" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_72eb92bb-63f8-4b07-a124-538e751321a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ServiceRevenueMember_c27a6825-ba49-4b99-b01a-733b5c4aaa7b" xlink:href="lii-20210930.xsd#lii_ServiceRevenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_086bf18e-05c6-4988-a36e-7e3cfa9b3270" xlink:to="loc_lii_ServiceRevenueMember_c27a6825-ba49-4b99-b01a-733b5c4aaa7b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_f37ad03e-535e-437d-ab87-4863caef5ba6" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_a3a5a77b-0d3f-463b-8ba8-cc3ab9d7a5bf" xlink:to="loc_srt_StatementGeographicalAxis_f37ad03e-535e-437d-ab87-4863caef5ba6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_f37ad03e-535e-437d-ab87-4863caef5ba6_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_f37ad03e-535e-437d-ab87-4863caef5ba6" xlink:to="loc_srt_SegmentGeographicalDomain_f37ad03e-535e-437d-ab87-4863caef5ba6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_8a73007a-0322-407e-9a13-51e4e01679a6" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_f37ad03e-535e-437d-ab87-4863caef5ba6" xlink:to="loc_srt_SegmentGeographicalDomain_8a73007a-0322-407e-9a13-51e4e01679a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_3824c1bc-b64d-4057-be56-144920ae07ae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerBasisOfPricingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_a3a5a77b-0d3f-463b-8ba8-cc3ab9d7a5bf" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_3824c1bc-b64d-4057-be56-144920ae07ae" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_3824c1bc-b64d-4057-be56-144920ae07ae_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerBasisOfPricingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_3824c1bc-b64d-4057-be56-144920ae07ae" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_3824c1bc-b64d-4057-be56-144920ae07ae_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_1cbb75b7-b553-4e47-b0fd-93b8d1ab2acc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerBasisOfPricingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_3824c1bc-b64d-4057-be56-144920ae07ae" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_1cbb75b7-b553-4e47-b0fd-93b8d1ab2acc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelDirectlyToConsumerMember_44419e9c-34f8-4f92-b9ca-97a3b20e8cf2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SalesChannelDirectlyToConsumerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_1cbb75b7-b553-4e47-b0fd-93b8d1ab2acc" xlink:to="loc_us-gaap_SalesChannelDirectlyToConsumerMember_44419e9c-34f8-4f92-b9ca-97a3b20e8cf2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerDurationAxis_ddec7a29-eaca-4ebc-8845-2b07dd8fdbbd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerDurationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_a3a5a77b-0d3f-463b-8ba8-cc3ab9d7a5bf" xlink:to="loc_us-gaap_ContractWithCustomerDurationAxis_ddec7a29-eaca-4ebc-8845-2b07dd8fdbbd" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerDurationDomain_ddec7a29-eaca-4ebc-8845-2b07dd8fdbbd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerDurationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerDurationAxis_ddec7a29-eaca-4ebc-8845-2b07dd8fdbbd" xlink:to="loc_us-gaap_ContractWithCustomerDurationDomain_ddec7a29-eaca-4ebc-8845-2b07dd8fdbbd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerDurationDomain_99093be4-f925-44b5-9f09-d122d1a3efa9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerDurationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerDurationAxis_ddec7a29-eaca-4ebc-8845-2b07dd8fdbbd" xlink:to="loc_us-gaap_ContractWithCustomerDurationDomain_99093be4-f925-44b5-9f09-d122d1a3efa9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_65c828b4-6491-436e-8588-146c98fe1f25" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TimingOfTransferOfGoodOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_a3a5a77b-0d3f-463b-8ba8-cc3ab9d7a5bf" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_65c828b4-6491-436e-8588-146c98fe1f25" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_65c828b4-6491-436e-8588-146c98fe1f25_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_65c828b4-6491-436e-8588-146c98fe1f25" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_65c828b4-6491-436e-8588-146c98fe1f25_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_3786acb0-fef1-422b-91d7-f9093788c83c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_65c828b4-6491-436e-8588-146c98fe1f25" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_3786acb0-fef1-422b-91d7-f9093788c83c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_4de88349-dea9-4861-946c-ddc00cf215f3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_a3a5a77b-0d3f-463b-8ba8-cc3ab9d7a5bf" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_4de88349-dea9-4861-946c-ddc00cf215f3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_4de88349-dea9-4861-946c-ddc00cf215f3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_4de88349-dea9-4861-946c-ddc00cf215f3" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_4de88349-dea9-4861-946c-ddc00cf215f3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_c4227647-d3e2-4f34-a822-793678e88a5e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_4de88349-dea9-4861-946c-ddc00cf215f3" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_c4227647-d3e2-4f34-a822-793678e88a5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelDirectlyToConsumerMember_9267f7fc-d438-438c-a251-07e5eb4cdbc8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SalesChannelDirectlyToConsumerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_c4227647-d3e2-4f34-a822-793678e88a5e" xlink:to="loc_us-gaap_SalesChannelDirectlyToConsumerMember_9267f7fc-d438-438c-a251-07e5eb4cdbc8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_1d82eeba-d852-4967-93d8-46f27ed31d03" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_a3a5a77b-0d3f-463b-8ba8-cc3ab9d7a5bf" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_1d82eeba-d852-4967-93d8-46f27ed31d03" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_1d82eeba-d852-4967-93d8-46f27ed31d03_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_1d82eeba-d852-4967-93d8-46f27ed31d03" xlink:to="loc_us-gaap_SegmentDomain_1d82eeba-d852-4967-93d8-46f27ed31d03_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_e1a76121-16aa-4415-802d-454a8ca39890" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_1d82eeba-d852-4967-93d8-46f27ed31d03" xlink:to="loc_us-gaap_SegmentDomain_e1a76121-16aa-4415-802d-454a8ca39890" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ResidentialHeatingAndCoolingMember_caa1071f-6347-4514-a046-d52732818c69" xlink:href="lii-20210930.xsd#lii_ResidentialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e1a76121-16aa-4415-802d-454a8ca39890" xlink:to="loc_lii_ResidentialHeatingAndCoolingMember_caa1071f-6347-4514-a046-d52732818c69" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_6ab95597-62fb-4f7c-922d-c69d71a55c2f" xlink:href="lii-20210930.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e1a76121-16aa-4415-802d-454a8ca39890" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_6ab95597-62fb-4f7c-922d-c69d71a55c2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_RefrigerationMember_9332959d-e22c-4e97-aa4a-000bd34bbc95" xlink:href="lii-20210930.xsd#lii_RefrigerationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e1a76121-16aa-4415-802d-454a8ca39890" xlink:to="loc_lii_RefrigerationMember_9332959d-e22c-4e97-aa4a-000bd34bbc95" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_156bb659-8d80-4382-9b97-9bc2350b2bdf" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_a3a5a77b-0d3f-463b-8ba8-cc3ab9d7a5bf" xlink:to="loc_srt_MajorCustomersAxis_156bb659-8d80-4382-9b97-9bc2350b2bdf" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_156bb659-8d80-4382-9b97-9bc2350b2bdf_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_156bb659-8d80-4382-9b97-9bc2350b2bdf" xlink:to="loc_srt_NameOfMajorCustomerDomain_156bb659-8d80-4382-9b97-9bc2350b2bdf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_e6e13d4f-1d52-48bd-b50e-67c67375946b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_156bb659-8d80-4382-9b97-9bc2350b2bdf" xlink:to="loc_srt_NameOfMajorCustomerDomain_e6e13d4f-1d52-48bd-b50e-67c67375946b" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/GoodwillDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#GoodwillDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/GoodwillDetails" xlink:type="extended" id="ia534c4958d8a4f1393d1770e5a2827a6_GoodwillDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_567536af-84e2-4b04-b7bc-0e9cd61779db" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillRollForward_291af9dd-8d44-4578-8a68-70cb94bdaeb2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_567536af-84e2-4b04-b7bc-0e9cd61779db" xlink:to="loc_us-gaap_GoodwillRollForward_291af9dd-8d44-4578-8a68-70cb94bdaeb2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_d350562b-f58b-4778-8e2e-2b6e74b8b878" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_291af9dd-8d44-4578-8a68-70cb94bdaeb2" xlink:to="loc_us-gaap_Goodwill_d350562b-f58b-4778-8e2e-2b6e74b8b878" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_a49f0dba-ad47-474c-b6e2-99524df5d5b8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillForeignCurrencyTranslationGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_291af9dd-8d44-4578-8a68-70cb94bdaeb2" xlink:to="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_a49f0dba-ad47-474c-b6e2-99524df5d5b8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_5093d2e5-eeb2-4327-a195-9d87864f0819" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Goodwill"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_f505d430-8e05-495e-81db-6a0bdb5680a8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_567536af-84e2-4b04-b7bc-0e9cd61779db" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_f505d430-8e05-495e-81db-6a0bdb5680a8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_94d3fe29-3175-42a5-9438-859de14b6958" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_f505d430-8e05-495e-81db-6a0bdb5680a8" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_94d3fe29-3175-42a5-9438-859de14b6958" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_94d3fe29-3175-42a5-9438-859de14b6958_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_94d3fe29-3175-42a5-9438-859de14b6958" xlink:to="loc_us-gaap_SegmentDomain_94d3fe29-3175-42a5-9438-859de14b6958_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_0cfc79cc-a9fc-4f55-9381-8343ed37f650" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_94d3fe29-3175-42a5-9438-859de14b6958" xlink:to="loc_us-gaap_SegmentDomain_0cfc79cc-a9fc-4f55-9381-8343ed37f650" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ResidentialHeatingAndCoolingMember_c300b281-04a0-498d-b484-39afbf426104" xlink:href="lii-20210930.xsd#lii_ResidentialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0cfc79cc-a9fc-4f55-9381-8343ed37f650" xlink:to="loc_lii_ResidentialHeatingAndCoolingMember_c300b281-04a0-498d-b484-39afbf426104" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_938be888-6d92-4745-8188-ba5f23d976cb" xlink:href="lii-20210930.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0cfc79cc-a9fc-4f55-9381-8343ed37f650" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_938be888-6d92-4745-8188-ba5f23d976cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_RefrigerationMember_3cf0eaa1-d116-44ea-b053-d82681440423" xlink:href="lii-20210930.xsd#lii_RefrigerationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0cfc79cc-a9fc-4f55-9381-8343ed37f650" xlink:to="loc_lii_RefrigerationMember_3cf0eaa1-d116-44ea-b053-d82681440423" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/DerivativesAOCLRelatedtoCashFlowHedgesDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#DerivativesAOCLRelatedtoCashFlowHedgesDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/DerivativesAOCLRelatedtoCashFlowHedgesDetails" xlink:type="extended" id="icc00f1b4a32f4416a65d135ff94b4674_DerivativesAOCLRelatedtoCashFlowHedgesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_4bf5f5a7-e713-47d9-b553-305b96ecd462" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1_36908a2c-973b-40d4-9e27-69b604cde9e8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_4bf5f5a7-e713-47d9-b553-305b96ecd462" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1_36908a2c-973b-40d4-9e27-69b604cde9e8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax_341a5ff5-4621-4031-974b-c27e3f00e050" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_4bf5f5a7-e713-47d9-b553-305b96ecd462" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax_341a5ff5-4621-4031-974b-c27e3f00e050" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesProvisionBenefitForTax_e47af594-4414-4c34-aae0-fe802bce0066" xlink:href="lii-20210930.xsd#lii_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesProvisionBenefitForTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_4bf5f5a7-e713-47d9-b553-305b96ecd462" xlink:to="loc_lii_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesProvisionBenefitForTax_e47af594-4414-4c34-aae0-fe802bce0066" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_92c91df5-c035-42c9-a7d2-1174d840cd55" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_4bf5f5a7-e713-47d9-b553-305b96ecd462" xlink:to="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_92c91df5-c035-42c9-a7d2-1174d840cd55" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_2f339bbd-ea89-47c1-930a-6bf2c59aec73" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_4bf5f5a7-e713-47d9-b553-305b96ecd462" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_2f339bbd-ea89-47c1-930a-6bf2c59aec73" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_100df044-3aa4-4f48-9c10-d9962ef5bf70" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_2f339bbd-ea89-47c1-930a-6bf2c59aec73" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_100df044-3aa4-4f48-9c10-d9962ef5bf70" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_100df044-3aa4-4f48-9c10-d9962ef5bf70_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_100df044-3aa4-4f48-9c10-d9962ef5bf70" xlink:to="loc_us-gaap_HedgingRelationshipDomain_100df044-3aa4-4f48-9c10-d9962ef5bf70_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_f77e97e6-a90a-4441-afdb-0d9c672f2063" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_100df044-3aa4-4f48-9c10-d9962ef5bf70" xlink:to="loc_us-gaap_HedgingRelationshipDomain_f77e97e6-a90a-4441-afdb-0d9c672f2063" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_541cfabc-5790-4433-a429-9cca0c665704" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_f77e97e6-a90a-4441-afdb-0d9c672f2063" xlink:to="loc_us-gaap_CashFlowHedgingMember_541cfabc-5790-4433-a429-9cca0c665704" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsOutstandingDebtObligationsDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#LinesofCreditandFinancingArrangementsOutstandingDebtObligationsDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsOutstandingDebtObligationsDetails" xlink:type="extended" id="if9018a34645e4fbeb0f8b82aba354c66_LinesofCreditandFinancingArrangementsOutstandingDebtObligationsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_49750139-31ff-49b5-a0dd-f52a85d1fc80" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrentAbstract_22024243-2b9e-4382-8666-9e415baabd5b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_49750139-31ff-49b5-a0dd-f52a85d1fc80" xlink:to="loc_us-gaap_LongTermDebtCurrentAbstract_22024243-2b9e-4382-8666-9e415baabd5b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityCurrent_61c84601-367e-4e3e-ae43-0bb5c0c7a31b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtCurrentAbstract_22024243-2b9e-4382-8666-9e415baabd5b" xlink:to="loc_us-gaap_FinanceLeaseLiabilityCurrent_61c84601-367e-4e3e-ae43-0bb5c0c7a31b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_1537d98f-ce1f-4e11-861f-e2e445fafe7f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtCurrentAbstract_22024243-2b9e-4382-8666-9e415baabd5b" xlink:to="loc_us-gaap_LongTermDebtCurrent_1537d98f-ce1f-4e11-861f-e2e445fafe7f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsCurrentGross_3907f734-725b-4e04-826b-d4f3b09f4b35" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredFinanceCostsCurrentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtCurrentAbstract_22024243-2b9e-4382-8666-9e415baabd5b" xlink:to="loc_us-gaap_DeferredFinanceCostsCurrentGross_3907f734-725b-4e04-826b-d4f3b09f4b35" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_c317412a-ff23-4740-a7ef-cbb3bfcd574e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtCurrentAbstract_22024243-2b9e-4382-8666-9e415baabd5b" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_c317412a-ff23-4740-a7ef-cbb3bfcd574e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract_f2ef9730-c9d5-4e57-a47f-0bfda816a639" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_49750139-31ff-49b5-a0dd-f52a85d1fc80" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract_f2ef9730-c9d5-4e57-a47f-0bfda816a639" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_b672d556-0c0f-4e92-829a-4d8febb33497" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract_f2ef9730-c9d5-4e57-a47f-0bfda816a639" xlink:to="loc_us-gaap_LongTermDebt_b672d556-0c0f-4e92-829a-4d8febb33497" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_bc50f379-6db3-4030-9899-a4a832dbeb94" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract_f2ef9730-c9d5-4e57-a47f-0bfda816a639" xlink:to="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_bc50f379-6db3-4030-9899-a4a832dbeb94" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNoncurrentGross_4a4e3043-14a3-4fad-8d69-19b87f0f71dc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredFinanceCostsNoncurrentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract_f2ef9730-c9d5-4e57-a47f-0bfda816a639" xlink:to="loc_us-gaap_DeferredFinanceCostsNoncurrentGross_4a4e3043-14a3-4fad-8d69-19b87f0f71dc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_64566267-2259-4c87-a9be-a0e2cd6a563b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract_f2ef9730-c9d5-4e57-a47f-0bfda816a639" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_64566267-2259-4c87-a9be-a0e2cd6a563b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtAndCapitalLeaseObligations_d41af0a3-555a-4a7a-8c72-05e1364bf23c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtAndCapitalLeaseObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_49750139-31ff-49b5-a0dd-f52a85d1fc80" xlink:to="loc_us-gaap_DebtAndCapitalLeaseObligations_d41af0a3-555a-4a7a-8c72-05e1364bf23c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_e769896c-0b76-41df-80a3-0595a751094d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_49750139-31ff-49b5-a0dd-f52a85d1fc80" xlink:to="loc_us-gaap_ShortTermBorrowings_e769896c-0b76-41df-80a3-0595a751094d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_e57a025e-f630-4778-8dc4-5830fc2aefed" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_49750139-31ff-49b5-a0dd-f52a85d1fc80" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_e57a025e-f630-4778-8dc4-5830fc2aefed" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_0911172f-a8ea-4bed-8ac6-528a19fb4d03" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_49750139-31ff-49b5-a0dd-f52a85d1fc80" xlink:to="loc_us-gaap_DebtInstrumentTable_0911172f-a8ea-4bed-8ac6-528a19fb4d03" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_cee9dc43-8d6d-4bf2-8b6a-108dab4dc774" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0911172f-a8ea-4bed-8ac6-528a19fb4d03" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_cee9dc43-8d6d-4bf2-8b6a-108dab4dc774" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_cee9dc43-8d6d-4bf2-8b6a-108dab4dc774_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_cee9dc43-8d6d-4bf2-8b6a-108dab4dc774" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_cee9dc43-8d6d-4bf2-8b6a-108dab4dc774_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_bfc8fe10-405f-463d-9135-e254ce1b5366" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_cee9dc43-8d6d-4bf2-8b6a-108dab4dc774" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_bfc8fe10-405f-463d-9135-e254ce1b5366" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignLineOfCreditMember_a3944784-cf54-4937-a659-a7feb5ca2e25" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForeignLineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_bfc8fe10-405f-463d-9135-e254ce1b5366" xlink:to="loc_us-gaap_ForeignLineOfCreditMember_a3944784-cf54-4937-a659-a7feb5ca2e25" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_ac2be206-2733-4ead-babf-719896a3102b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0911172f-a8ea-4bed-8ac6-528a19fb4d03" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_ac2be206-2733-4ead-babf-719896a3102b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_ac2be206-2733-4ead-babf-719896a3102b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_ac2be206-2733-4ead-babf-719896a3102b" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_ac2be206-2733-4ead-babf-719896a3102b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_bc2fdcff-9a95-4dd5-9fb3-e3f0fc119dfb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_ac2be206-2733-4ead-babf-719896a3102b" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_bc2fdcff-9a95-4dd5-9fb3-e3f0fc119dfb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticLineOfCreditMember_845fe0a0-3fc3-41c1-a5ff-13b14ad1b935" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DomesticLineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_bc2fdcff-9a95-4dd5-9fb3-e3f0fc119dfb" xlink:to="loc_us-gaap_DomesticLineOfCreditMember_845fe0a0-3fc3-41c1-a5ff-13b14ad1b935" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_AssetSecuritizationMember_b93f7cf1-1ac6-42d5-9f93-5e27237cf32b" xlink:href="lii-20210930.xsd#lii_AssetSecuritizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_bc2fdcff-9a95-4dd5-9fb3-e3f0fc119dfb" xlink:to="loc_lii_AssetSecuritizationMember_b93f7cf1-1ac6-42d5-9f93-5e27237cf32b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_118ff2fc-1a59-4bdc-b3b6-2a7e68b8f58f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_bc2fdcff-9a95-4dd5-9fb3-e3f0fc119dfb" xlink:to="loc_us-gaap_SeniorNotesMember_118ff2fc-1a59-4bdc-b3b6-2a7e68b8f58f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsForeignObligationsDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#LinesofCreditandFinancingArrangementsForeignObligationsDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsForeignObligationsDetails" xlink:type="extended" id="ifa6340f563434769bfda71456d2435e6_LinesofCreditandFinancingArrangementsForeignObligationsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtLineItems_618409f3-da7e-47a1-a990-923030968548" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_a0766efa-f47e-480b-9644-995674112b41" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_618409f3-da7e-47a1-a990-923030968548" xlink:to="loc_us-gaap_ShortTermBorrowings_a0766efa-f47e-480b-9644-995674112b41" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromShortTermDebt_7d8a414c-5cbe-4fcf-83d4-f1197ac56264" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromShortTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_618409f3-da7e-47a1-a990-923030968548" xlink:to="loc_us-gaap_ProceedsFromShortTermDebt_7d8a414c-5cbe-4fcf-83d4-f1197ac56264" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfShortTermDebt_1408daac-b670-4677-b334-fba92772f669" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RepaymentsOfShortTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_618409f3-da7e-47a1-a990-923030968548" xlink:to="loc_us-gaap_RepaymentsOfShortTermDebt_1408daac-b670-4677-b334-fba92772f669" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShortTermDebtTable_08234aad-1ff2-4c26-98c4-b59e2c5e31e9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShortTermDebtTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortTermDebtLineItems_618409f3-da7e-47a1-a990-923030968548" xlink:to="loc_us-gaap_ScheduleOfShortTermDebtTable_08234aad-1ff2-4c26-98c4-b59e2c5e31e9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_0722102f-1fb2-4a22-a7de-3c6a880fe86d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_08234aad-1ff2-4c26-98c4-b59e2c5e31e9" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_0722102f-1fb2-4a22-a7de-3c6a880fe86d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_0722102f-1fb2-4a22-a7de-3c6a880fe86d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_0722102f-1fb2-4a22-a7de-3c6a880fe86d" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_0722102f-1fb2-4a22-a7de-3c6a880fe86d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_20347015-a233-4fb6-94a5-88e76c8362d9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_0722102f-1fb2-4a22-a7de-3c6a880fe86d" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_20347015-a233-4fb6-94a5-88e76c8362d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignLineOfCreditMember_eef6eea6-20c2-4e16-8538-76613aca967b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForeignLineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_20347015-a233-4fb6-94a5-88e76c8362d9" xlink:to="loc_us-gaap_ForeignLineOfCreditMember_eef6eea6-20c2-4e16-8538-76613aca967b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsAssetSecuritizationProgramDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#LinesofCreditandFinancingArrangementsAssetSecuritizationProgramDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsAssetSecuritizationProgramDetails" xlink:type="extended" id="ia9b0d0e5940f4402be7755368e1c299f_LinesofCreditandFinancingArrangementsAssetSecuritizationProgramDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_39bae192-4c76-4ca9-9bb4-0d0a6df54feb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_AssetSecuritizationBorrowingCapacity_91994991-e5ac-4051-88ec-ca8adc0b1b90" xlink:href="lii-20210930.xsd#lii_AssetSecuritizationBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_39bae192-4c76-4ca9-9bb4-0d0a6df54feb" xlink:to="loc_lii_AssetSecuritizationBorrowingCapacity_91994991-e5ac-4051-88ec-ca8adc0b1b90" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_MaximumSecuritizationAsPercentageOfNetPoolBalance_9d93a0bd-e27d-4061-a811-11ad74371a86" xlink:href="lii-20210930.xsd#lii_MaximumSecuritizationAsPercentageOfNetPoolBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_39bae192-4c76-4ca9-9bb4-0d0a6df54feb" xlink:to="loc_lii_MaximumSecuritizationAsPercentageOfNetPoolBalance_9d93a0bd-e27d-4061-a811-11ad74371a86" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ProgramFee_6e8345c6-a878-44fc-90c3-60bd76d4cf6e" xlink:href="lii-20210930.xsd#lii_ProgramFee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_39bae192-4c76-4ca9-9bb4-0d0a6df54feb" xlink:to="loc_lii_ProgramFee_6e8345c6-a878-44fc-90c3-60bd76d4cf6e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_AverageFloatingCommercialPaperRate_97ea92c8-d0a4-40a9-a968-4e07841730e6" xlink:href="lii-20210930.xsd#lii_AverageFloatingCommercialPaperRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_39bae192-4c76-4ca9-9bb4-0d0a6df54feb" xlink:to="loc_lii_AverageFloatingCommercialPaperRate_97ea92c8-d0a4-40a9-a968-4e07841730e6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_PercentageOfMaximumAvailableAmountUsedToChargeUnusedFee_89408086-9f9a-4ea6-8507-e54442c5e166" xlink:href="lii-20210930.xsd#lii_PercentageOfMaximumAvailableAmountUsedToChargeUnusedFee"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_39bae192-4c76-4ca9-9bb4-0d0a6df54feb" xlink:to="loc_lii_PercentageOfMaximumAvailableAmountUsedToChargeUnusedFee_89408086-9f9a-4ea6-8507-e54442c5e166" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_FixedRateOfAgreement_91f14791-2aa8-4575-b3da-14b7cde4a7a8" xlink:href="lii-20210930.xsd#lii_FixedRateOfAgreement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_39bae192-4c76-4ca9-9bb4-0d0a6df54feb" xlink:to="loc_lii_FixedRateOfAgreement_91f14791-2aa8-4575-b3da-14b7cde4a7a8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization_91565e3f-26d2-44e3-ab2f-ea2253ca543f" xlink:href="lii-20210930.xsd#lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_39bae192-4c76-4ca9-9bb4-0d0a6df54feb" xlink:to="loc_lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization_91565e3f-26d2-44e3-ab2f-ea2253ca543f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_027c345e-e6ff-4288-858c-392634369764" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_39bae192-4c76-4ca9-9bb4-0d0a6df54feb" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_027c345e-e6ff-4288-858c-392634369764" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_cd7a59fc-9599-4ac0-a647-b09d0e9386de" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_027c345e-e6ff-4288-858c-392634369764" xlink:to="loc_srt_RangeAxis_cd7a59fc-9599-4ac0-a647-b09d0e9386de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_cd7a59fc-9599-4ac0-a647-b09d0e9386de_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_cd7a59fc-9599-4ac0-a647-b09d0e9386de" xlink:to="loc_srt_RangeMember_cd7a59fc-9599-4ac0-a647-b09d0e9386de_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_ad9d3249-6f63-405c-b345-111a2f3dd38d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_cd7a59fc-9599-4ac0-a647-b09d0e9386de" xlink:to="loc_srt_RangeMember_ad9d3249-6f63-405c-b345-111a2f3dd38d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_36940fda-9d4b-47c9-8258-05d53c1aea25" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_ad9d3249-6f63-405c-b345-111a2f3dd38d" xlink:to="loc_srt_MinimumMember_36940fda-9d4b-47c9-8258-05d53c1aea25" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_f611f92e-9dfa-4404-b1d4-9d09f90d977b" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_ad9d3249-6f63-405c-b345-111a2f3dd38d" xlink:to="loc_srt_MaximumMember_f611f92e-9dfa-4404-b1d4-9d09f90d977b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_4145f1c7-3407-4cae-8d6d-e747d5d6c1a7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_027c345e-e6ff-4288-858c-392634369764" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_4145f1c7-3407-4cae-8d6d-e747d5d6c1a7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_4145f1c7-3407-4cae-8d6d-e747d5d6c1a7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_4145f1c7-3407-4cae-8d6d-e747d5d6c1a7" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_4145f1c7-3407-4cae-8d6d-e747d5d6c1a7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_56d7198f-ae44-46bf-96c1-508757ff4a68" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_4145f1c7-3407-4cae-8d6d-e747d5d6c1a7" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_56d7198f-ae44-46bf-96c1-508757ff4a68" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_7a9300ef-716f-44c3-b9a3-09dda6fcfb3a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_56d7198f-ae44-46bf-96c1-508757ff4a68" xlink:to="loc_us-gaap_SeniorNotesMember_7a9300ef-716f-44c3-b9a3-09dda6fcfb3a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsDomesticCreditFacilityDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#LinesofCreditandFinancingArrangementsDomesticCreditFacilityDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsDomesticCreditFacilityDetails" xlink:type="extended" id="ie40f6814735840229f040727de18fdc3_LinesofCreditandFinancingArrangementsDomesticCreditFacilityDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_ff564f75-6588-4838-ba0d-a9420a186d13" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_ff564f75-6588-4838-ba0d-a9420a186d13" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_LineOfCreditFacilityNumberOfExtensions_8b085b6e-b2da-4c59-84af-15c52b3be4f6" xlink:href="lii-20210930.xsd#lii_LineOfCreditFacilityNumberOfExtensions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_lii_LineOfCreditFacilityNumberOfExtensions_8b085b6e-b2da-4c59-84af-15c52b3be4f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_LineOfCreditFacilityExtensionPeriod_de304d59-92ed-4cb6-b77f-5a226fdfc97c" xlink:href="lii-20210930.xsd#lii_LineOfCreditFacilityExtensionPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_lii_LineOfCreditFacilityExtensionPeriod_de304d59-92ed-4cb6-b77f-5a226fdfc97c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_LineOfCreditFacilityAccordionFeatureHigherBorrowingCapacityOption_9c87a56b-490f-496a-a6d7-aebe6b207cfb" xlink:href="lii-20210930.xsd#lii_LineOfCreditFacilityAccordionFeatureHigherBorrowingCapacityOption"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_lii_LineOfCreditFacilityAccordionFeatureHigherBorrowingCapacityOption_9c87a56b-490f-496a-a6d7-aebe6b207cfb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentCovenantLeverageRatioMaximumAllowed_9a6d0f19-fbbd-4263-9130-905a23ca3749" xlink:href="lii-20210930.xsd#lii_DebtInstrumentCovenantLeverageRatioMaximumAllowed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_lii_DebtInstrumentCovenantLeverageRatioMaximumAllowed_9a6d0f19-fbbd-4263-9130-905a23ca3749" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentCovenantLeverageRatioMaximumAllowedAfterMaterialAcquisition_15aa7c94-5db0-463a-b91c-d6e1f6606db2" xlink:href="lii-20210930.xsd#lii_DebtInstrumentCovenantLeverageRatioMaximumAllowedAfterMaterialAcquisition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_lii_DebtInstrumentCovenantLeverageRatioMaximumAllowedAfterMaterialAcquisition_15aa7c94-5db0-463a-b91c-d6e1f6606db2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentCovenantOtherIndebtednessThresholdUponDefault_046d6bff-69b3-423f-b486-55e721a1b7cb" xlink:href="lii-20210930.xsd#lii_DebtInstrumentCovenantOtherIndebtednessThresholdUponDefault"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_lii_DebtInstrumentCovenantOtherIndebtednessThresholdUponDefault_046d6bff-69b3-423f-b486-55e721a1b7cb" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentCovenantJudgementThresholdUponDefault_f659a3d3-0ab2-493c-8cc1-c954468674db" xlink:href="lii-20210930.xsd#lii_DebtInstrumentCovenantJudgementThresholdUponDefault"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_lii_DebtInstrumentCovenantJudgementThresholdUponDefault_f659a3d3-0ab2-493c-8cc1-c954468674db" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_9c3e8b1b-6e2c-4327-94ab-2da522801225" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_9c3e8b1b-6e2c-4327-94ab-2da522801225" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentSeriesOfDebtNotes_96696e96-55cc-452a-91cb-6f7e52d3b015" xlink:href="lii-20210930.xsd#lii_DebtInstrumentSeriesOfDebtNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_lii_DebtInstrumentSeriesOfDebtNotes_96696e96-55cc-452a-91cb-6f7e52d3b015" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_423d81d2-1093-4f56-8dd8-1271a982ffc5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_us-gaap_LineOfCredit_423d81d2-1093-4f56-8dd8-1271a982ffc5" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_RevolvingCreditFacilityCommittedToStandByLettersOfCredit_b62207ce-547a-48cc-bf7a-4a294a0ecd19" xlink:href="lii-20210930.xsd#lii_RevolvingCreditFacilityCommittedToStandByLettersOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_lii_RevolvingCreditFacilityCommittedToStandByLettersOfCredit_b62207ce-547a-48cc-bf7a-4a294a0ecd19" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_41d72364-53f5-4afd-8ee6-233697092663" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_41d72364-53f5-4afd-8ee6-233697092663" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization_300109e2-a41c-45f1-9ee9-f1628d9d2975" xlink:href="lii-20210930.xsd#lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization_300109e2-a41c-45f1-9ee9-f1628d9d2975" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_cd26495e-f3d1-4a97-a695-d94cb57e8cca" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_cd26495e-f3d1-4a97-a695-d94cb57e8cca" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_c09a5d3b-bb98-4d8b-bea5-9de417b1346a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_637c5eb9-26e1-40ab-a22b-02e16197f64f" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_c09a5d3b-bb98-4d8b-bea5-9de417b1346a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_6bcd2624-fd92-470a-94af-3e68580d558a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_c09a5d3b-bb98-4d8b-bea5-9de417b1346a" xlink:to="loc_us-gaap_DebtInstrumentAxis_6bcd2624-fd92-470a-94af-3e68580d558a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_6bcd2624-fd92-470a-94af-3e68580d558a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_6bcd2624-fd92-470a-94af-3e68580d558a" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_6bcd2624-fd92-470a-94af-3e68580d558a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_ae70194a-38f9-4ab4-a20d-503b80cdcde3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_6bcd2624-fd92-470a-94af-3e68580d558a" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_ae70194a-38f9-4ab4-a20d-503b80cdcde3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_1ab751ee-8690-43d9-952a-dcbf7c0f7bf7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_ae70194a-38f9-4ab4-a20d-503b80cdcde3" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_1ab751ee-8690-43d9-952a-dcbf7c0f7bf7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2025NotesMember_e23e014a-ae75-49cf-b11b-5d2de79dbf0d" xlink:href="lii-20210930.xsd#lii_A2025NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_ae70194a-38f9-4ab4-a20d-503b80cdcde3" xlink:to="loc_lii_A2025NotesMember_e23e014a-ae75-49cf-b11b-5d2de79dbf0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2027NotesMember_2e8a885a-ae78-481f-93d7-c74b446f01e4" xlink:href="lii-20210930.xsd#lii_A2027NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_ae70194a-38f9-4ab4-a20d-503b80cdcde3" xlink:to="loc_lii_A2027NotesMember_2e8a885a-ae78-481f-93d7-c74b446f01e4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_c9702ef4-e75b-4def-95cc-0fcbccfc01fb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_c09a5d3b-bb98-4d8b-bea5-9de417b1346a" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_c9702ef4-e75b-4def-95cc-0fcbccfc01fb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_c9702ef4-e75b-4def-95cc-0fcbccfc01fb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_c9702ef4-e75b-4def-95cc-0fcbccfc01fb" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_c9702ef4-e75b-4def-95cc-0fcbccfc01fb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_ae1ec12b-8aaf-4131-b11c-a90d2164ce4a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_c9702ef4-e75b-4def-95cc-0fcbccfc01fb" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_ae1ec12b-8aaf-4131-b11c-a90d2164ce4a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MediumTermNotesMember_b4073357-9677-4084-ad6d-1248c6364207" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MediumTermNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_ae1ec12b-8aaf-4131-b11c-a90d2164ce4a" xlink:to="loc_us-gaap_MediumTermNotesMember_b4073357-9677-4084-ad6d-1248c6364207" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_c4318f50-7351-4f82-827a-a438f3b25ea5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_ae1ec12b-8aaf-4131-b11c-a90d2164ce4a" xlink:to="loc_us-gaap_LineOfCreditMember_c4318f50-7351-4f82-827a-a438f3b25ea5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_919f9d7d-2f70-416c-a70f-80490b169c62" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_ae1ec12b-8aaf-4131-b11c-a90d2164ce4a" xlink:to="loc_us-gaap_SeniorNotesMember_919f9d7d-2f70-416c-a70f-80490b169c62" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_a1e5226f-ecd5-454a-bd36-79ad353ae251" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_c09a5d3b-bb98-4d8b-bea5-9de417b1346a" xlink:to="loc_us-gaap_CreditFacilityAxis_a1e5226f-ecd5-454a-bd36-79ad353ae251" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_a1e5226f-ecd5-454a-bd36-79ad353ae251_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_a1e5226f-ecd5-454a-bd36-79ad353ae251" xlink:to="loc_us-gaap_CreditFacilityDomain_a1e5226f-ecd5-454a-bd36-79ad353ae251_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_81aa02b4-d650-443f-8d46-ab536b66d712" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_a1e5226f-ecd5-454a-bd36-79ad353ae251" xlink:to="loc_us-gaap_CreditFacilityDomain_81aa02b4-d650-443f-8d46-ab536b66d712" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_663df7aa-3c2d-49f0-a1e4-c4ee59567b9d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_81aa02b4-d650-443f-8d46-ab536b66d712" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_663df7aa-3c2d-49f0-a1e4-c4ee59567b9d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BridgeLoanMember_c97e2d63-0d72-4c2c-b217-55cd5c967cec" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BridgeLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevolvingCreditFacilityMember_663df7aa-3c2d-49f0-a1e4-c4ee59567b9d" xlink:to="loc_us-gaap_BridgeLoanMember_c97e2d63-0d72-4c2c-b217-55cd5c967cec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_9191077a-79a2-4a2d-869e-29003fd24550" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevolvingCreditFacilityMember_663df7aa-3c2d-49f0-a1e4-c4ee59567b9d" xlink:to="loc_us-gaap_LetterOfCreditMember_9191077a-79a2-4a2d-869e-29003fd24550" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_3e82d097-7085-43cf-80bf-9a0555b5be40" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_81aa02b4-d650-443f-8d46-ab536b66d712" xlink:to="loc_us-gaap_LineOfCreditMember_3e82d097-7085-43cf-80bf-9a0555b5be40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DomesticCreditFacilityMember_3a1d444c-7cd4-45f8-a2f2-c88babc9fb6c" xlink:href="lii-20210930.xsd#lii_DomesticCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_81aa02b4-d650-443f-8d46-ab536b66d712" xlink:to="loc_lii_DomesticCreditFacilityMember_3a1d444c-7cd4-45f8-a2f2-c88babc9fb6c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CurrencyAxis_08565caf-a090-43fe-a993-8aad441beb9c" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CurrencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_c09a5d3b-bb98-4d8b-bea5-9de417b1346a" xlink:to="loc_srt_CurrencyAxis_08565caf-a090-43fe-a993-8aad441beb9c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_AllCurrenciesDomain_08565caf-a090-43fe-a993-8aad441beb9c_default" xlink:href="https://xbrl.sec.gov/currency/2021/currency-2021.xsd#currency_AllCurrenciesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CurrencyAxis_08565caf-a090-43fe-a993-8aad441beb9c" xlink:to="loc_currency_AllCurrenciesDomain_08565caf-a090-43fe-a993-8aad441beb9c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_AllCurrenciesDomain_03ac4353-fd1c-4c91-b6db-a76123ea5b04" xlink:href="https://xbrl.sec.gov/currency/2021/currency-2021.xsd#currency_AllCurrenciesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CurrencyAxis_08565caf-a090-43fe-a993-8aad441beb9c" xlink:to="loc_currency_AllCurrenciesDomain_03ac4353-fd1c-4c91-b6db-a76123ea5b04" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_currency_USD_264c0d91-b234-4d76-a06d-275a1268a513" xlink:href="https://xbrl.sec.gov/currency/2021/currency-2021.xsd#currency_USD"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_currency_AllCurrenciesDomain_03ac4353-fd1c-4c91-b6db-a76123ea5b04" xlink:to="loc_currency_USD_264c0d91-b234-4d76-a06d-275a1268a513" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsWeightedAverageBorrowingRateDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#LinesofCreditandFinancingArrangementsWeightedAverageBorrowingRateDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsWeightedAverageBorrowingRateDetails" xlink:type="extended" id="i4d1f00215d99444eba41092b09ab1f43_LinesofCreditandFinancingArrangementsWeightedAverageBorrowingRateDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_93456cc6-45ec-4570-901c-38a1a33547ef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_4445224c-69db-40a8-be67-95312316d09f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_93456cc6-45ec-4570-901c-38a1a33547ef" xlink:to="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_4445224c-69db-40a8-be67-95312316d09f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_3cfba53c-41e6-45f7-8aee-6fbe8df93399" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_93456cc6-45ec-4570-901c-38a1a33547ef" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_3cfba53c-41e6-45f7-8aee-6fbe8df93399" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_b6f2a2cf-caf3-46e8-a08f-f8d5ebc85d44" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_3cfba53c-41e6-45f7-8aee-6fbe8df93399" xlink:to="loc_us-gaap_DebtInstrumentAxis_b6f2a2cf-caf3-46e8-a08f-f8d5ebc85d44" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_b6f2a2cf-caf3-46e8-a08f-f8d5ebc85d44_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_b6f2a2cf-caf3-46e8-a08f-f8d5ebc85d44" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_b6f2a2cf-caf3-46e8-a08f-f8d5ebc85d44_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_f1d8dad9-7881-4315-8e8d-887337f2c7b9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_b6f2a2cf-caf3-46e8-a08f-f8d5ebc85d44" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_f1d8dad9-7881-4315-8e8d-887337f2c7b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_4e4701d2-4b38-424f-bb41-4eb67faed2a8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f1d8dad9-7881-4315-8e8d-887337f2c7b9" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_4e4701d2-4b38-424f-bb41-4eb67faed2a8" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsCreditFacilityRatiosDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#LinesofCreditandFinancingArrangementsCreditFacilityRatiosDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsCreditFacilityRatiosDetails" xlink:type="extended" id="i0dcd83fe751442c3879127dcebe085cd_LinesofCreditandFinancingArrangementsCreditFacilityRatiosDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_2c178e5f-5c91-4189-8c9e-ec1f6108b2cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_139f75c5-81dd-4a9e-a835-4f0e49865c9f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_2c178e5f-5c91-4189-8c9e-ec1f6108b2cf" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_139f75c5-81dd-4a9e-a835-4f0e49865c9f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_5374477c-e8e9-40b9-b09d-8063e6328cb3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_139f75c5-81dd-4a9e-a835-4f0e49865c9f" xlink:to="loc_us-gaap_CreditFacilityAxis_5374477c-e8e9-40b9-b09d-8063e6328cb3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_5374477c-e8e9-40b9-b09d-8063e6328cb3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_5374477c-e8e9-40b9-b09d-8063e6328cb3" xlink:to="loc_us-gaap_CreditFacilityDomain_5374477c-e8e9-40b9-b09d-8063e6328cb3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_e22e316a-ad9c-42a9-9e2e-460781475ee3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_5374477c-e8e9-40b9-b09d-8063e6328cb3" xlink:to="loc_us-gaap_CreditFacilityDomain_e22e316a-ad9c-42a9-9e2e-460781475ee3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_d599388a-936e-46f0-8451-c39919a1d371" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_e22e316a-ad9c-42a9-9e2e-460781475ee3" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_d599388a-936e-46f0-8451-c39919a1d371" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_d117b46b-f404-4b88-a23d-8765537efca2" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_139f75c5-81dd-4a9e-a835-4f0e49865c9f" xlink:to="loc_srt_RangeAxis_d117b46b-f404-4b88-a23d-8765537efca2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_d117b46b-f404-4b88-a23d-8765537efca2_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_d117b46b-f404-4b88-a23d-8765537efca2" xlink:to="loc_srt_RangeMember_d117b46b-f404-4b88-a23d-8765537efca2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_d63267f1-edc8-497b-8f23-8296769244d6" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_d117b46b-f404-4b88-a23d-8765537efca2" xlink:to="loc_srt_RangeMember_d63267f1-edc8-497b-8f23-8296769244d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_427c8349-eac0-4f30-80f3-71691bdc9ae3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_d63267f1-edc8-497b-8f23-8296769244d6" xlink:to="loc_srt_MaximumMember_427c8349-eac0-4f30-80f3-71691bdc9ae3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_97868cb1-180d-4afa-9f0e-e2cb00d7668a" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_d63267f1-edc8-497b-8f23-8296769244d6" xlink:to="loc_srt_MinimumMember_97868cb1-180d-4afa-9f0e-e2cb00d7668a" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsSeniorUnsecuredNotesDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#LinesofCreditandFinancingArrangementsSeniorUnsecuredNotesDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsSeniorUnsecuredNotesDetails" xlink:type="extended" id="id2dc5681a8724c6380a523ef1307bcc3_LinesofCreditandFinancingArrangementsSeniorUnsecuredNotesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_bc28ba2a-ccaa-4675-95f5-99128e68ef33" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentSeriesOfDebtNotes_82d52ab8-11af-443b-817b-cf67f5eaf655" xlink:href="lii-20210930.xsd#lii_DebtInstrumentSeriesOfDebtNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bc28ba2a-ccaa-4675-95f5-99128e68ef33" xlink:to="loc_lii_DebtInstrumentSeriesOfDebtNotes_82d52ab8-11af-443b-817b-cf67f5eaf655" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_dd884c4f-e2f0-4acb-8e57-2307b1794eaa" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bc28ba2a-ccaa-4675-95f5-99128e68ef33" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_dd884c4f-e2f0-4acb-8e57-2307b1794eaa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_7f5eeef3-80f9-42a8-b5de-49ca7f5a0594" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bc28ba2a-ccaa-4675-95f5-99128e68ef33" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_7f5eeef3-80f9-42a8-b5de-49ca7f5a0594" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentMaturityDate_d352f405-ac21-4d0c-aa8f-44cad473657c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentMaturityDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bc28ba2a-ccaa-4675-95f5-99128e68ef33" xlink:to="loc_us-gaap_DebtInstrumentMaturityDate_d352f405-ac21-4d0c-aa8f-44cad473657c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization_919338eb-3da7-4479-9b77-09bdd0afb873" xlink:href="lii-20210930.xsd#lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bc28ba2a-ccaa-4675-95f5-99128e68ef33" xlink:to="loc_lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization_919338eb-3da7-4479-9b77-09bdd0afb873" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_PeriodForRescissionOfAcceleratedDebt_e2be6c2e-22b9-436d-b6ee-8df4fe2fd1e8" xlink:href="lii-20210930.xsd#lii_PeriodForRescissionOfAcceleratedDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bc28ba2a-ccaa-4675-95f5-99128e68ef33" xlink:to="loc_lii_PeriodForRescissionOfAcceleratedDebt_e2be6c2e-22b9-436d-b6ee-8df4fe2fd1e8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_1b8ca219-f90d-4e0b-88ca-8df6400f9f57" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_bc28ba2a-ccaa-4675-95f5-99128e68ef33" xlink:to="loc_us-gaap_DebtInstrumentTable_1b8ca219-f90d-4e0b-88ca-8df6400f9f57" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_399bc921-c28f-4db9-acd5-c9092cb2f478" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1b8ca219-f90d-4e0b-88ca-8df6400f9f57" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_399bc921-c28f-4db9-acd5-c9092cb2f478" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_399bc921-c28f-4db9-acd5-c9092cb2f478_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_399bc921-c28f-4db9-acd5-c9092cb2f478" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_399bc921-c28f-4db9-acd5-c9092cb2f478_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_3fe29146-0c1d-4b75-855b-922b72cf3886" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_399bc921-c28f-4db9-acd5-c9092cb2f478" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_3fe29146-0c1d-4b75-855b-922b72cf3886" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_61bf5c78-e8a0-4022-ad84-192f2f050f27" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3fe29146-0c1d-4b75-855b-922b72cf3886" xlink:to="loc_us-gaap_SeniorNotesMember_61bf5c78-e8a0-4022-ad84-192f2f050f27" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_53282421-3538-4d01-a07a-8099eed4ff2b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_1b8ca219-f90d-4e0b-88ca-8df6400f9f57" xlink:to="loc_us-gaap_DebtInstrumentAxis_53282421-3538-4d01-a07a-8099eed4ff2b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_53282421-3538-4d01-a07a-8099eed4ff2b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_53282421-3538-4d01-a07a-8099eed4ff2b" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_53282421-3538-4d01-a07a-8099eed4ff2b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_007dabb8-1611-4cc9-bdff-45916cb16290" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_53282421-3538-4d01-a07a-8099eed4ff2b" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_007dabb8-1611-4cc9-bdff-45916cb16290" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2025NotesMember_dad468d9-7967-4f00-a1e6-3b0687fa0556" xlink:href="lii-20210930.xsd#lii_A2025NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_007dabb8-1611-4cc9-bdff-45916cb16290" xlink:to="loc_lii_A2025NotesMember_dad468d9-7967-4f00-a1e6-3b0687fa0556" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2027NotesMember_93afc931-b3c4-4de8-a194-626d35e48253" xlink:href="lii-20210930.xsd#lii_A2027NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_007dabb8-1611-4cc9-bdff-45916cb16290" xlink:to="loc_lii_A2027NotesMember_93afc931-b3c4-4de8-a194-626d35e48253" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2023NotesMember_4fbc8cc8-1a36-4edc-8e6c-cc405e00695b" xlink:href="lii-20210930.xsd#lii_A2023NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_007dabb8-1611-4cc9-bdff-45916cb16290" xlink:to="loc_lii_A2023NotesMember_4fbc8cc8-1a36-4edc-8e6c-cc405e00695b" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/ComprehensiveIncomeReclassificationoutofAOCLDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#ComprehensiveIncomeReclassificationoutofAOCLDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/ComprehensiveIncomeReclassificationoutofAOCLDetails" xlink:type="extended" id="i82b05c90651e4350821e1a6a567cfc70_ComprehensiveIncomeReclassificationoutofAOCLDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_475da88f-b046-422f-859e-06d2af1a7ebe" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_ef8db490-68f0-4663-829e-c3237f3e4f10" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_475da88f-b046-422f-859e-06d2af1a7ebe" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_ef8db490-68f0-4663-829e-c3237f3e4f10" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_37ff963c-e349-4095-a666-5e63756dc04e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_475da88f-b046-422f-859e-06d2af1a7ebe" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_37ff963c-e349-4095-a666-5e63756dc04e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_721dbc81-4a63-40cc-afaa-2e459a72464e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_475da88f-b046-422f-859e-06d2af1a7ebe" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_721dbc81-4a63-40cc-afaa-2e459a72464e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_67e8f835-a6d8-4a9f-8d56-cd7868bb74ef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_475da88f-b046-422f-859e-06d2af1a7ebe" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_67e8f835-a6d8-4a9f-8d56-cd7868bb74ef" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_791a0191-e544-4d33-9c04-3f95365f295e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_67e8f835-a6d8-4a9f-8d56-cd7868bb74ef" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_791a0191-e544-4d33-9c04-3f95365f295e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_791a0191-e544-4d33-9c04-3f95365f295e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_791a0191-e544-4d33-9c04-3f95365f295e" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_791a0191-e544-4d33-9c04-3f95365f295e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_a5ac6ad7-055d-462f-8ba8-ca8b4c89ef94" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_791a0191-e544-4d33-9c04-3f95365f295e" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_a5ac6ad7-055d-462f-8ba8-ca8b4c89ef94" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_1a82efa1-344f-4fd9-ae78-f092acc8ad45" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_a5ac6ad7-055d-462f-8ba8-ca8b4c89ef94" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_1a82efa1-344f-4fd9-ae78-f092acc8ad45" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_f4643b37-834f-4dcc-8220-4bec24ea7f0f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_67e8f835-a6d8-4a9f-8d56-cd7868bb74ef" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_f4643b37-834f-4dcc-8220-4bec24ea7f0f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_f4643b37-834f-4dcc-8220-4bec24ea7f0f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_f4643b37-834f-4dcc-8220-4bec24ea7f0f" xlink:to="loc_us-gaap_EquityComponentDomain_f4643b37-834f-4dcc-8220-4bec24ea7f0f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_1cc58cea-983a-4f19-8d17-a41d8d45b933" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_f4643b37-834f-4dcc-8220-4bec24ea7f0f" xlink:to="loc_us-gaap_EquityComponentDomain_1cc58cea-983a-4f19-8d17-a41d8d45b933" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_61093d89-e75d-48d4-aade-71cd06fe371d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_1cc58cea-983a-4f19-8d17-a41d8d45b933" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_61093d89-e75d-48d4-aade-71cd06fe371d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_b9b81f19-3a34-426a-bd88-9edd576e132a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_1cc58cea-983a-4f19-8d17-a41d8d45b933" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_b9b81f19-3a34-426a-bd88-9edd576e132a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_d3f5c095-8972-435b-9e5e-b5b568648df2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_1cc58cea-983a-4f19-8d17-a41d8d45b933" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_d3f5c095-8972-435b-9e5e-b5b568648df2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_91c66681-2996-4a8a-a327-befafaa6c3f6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_67e8f835-a6d8-4a9f-8d56-cd7868bb74ef" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_91c66681-2996-4a8a-a327-befafaa6c3f6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_91c66681-2996-4a8a-a327-befafaa6c3f6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_91c66681-2996-4a8a-a327-befafaa6c3f6" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_91c66681-2996-4a8a-a327-befafaa6c3f6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_06d81104-1882-479e-b5d4-6a79f813f7b2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_91c66681-2996-4a8a-a327-befafaa6c3f6" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_06d81104-1882-479e-b5d4-6a79f813f7b2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_e51ce548-7493-421d-a3b3-929b03821328" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_06d81104-1882-479e-b5d4-6a79f813f7b2" xlink:to="loc_us-gaap_CommodityContractMember_e51ce548-7493-421d-a3b3-929b03821328" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/ComprehensiveIncomeChangesinAOCLDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#ComprehensiveIncomeChangesinAOCLDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/ComprehensiveIncomeChangesinAOCLDetails" xlink:type="extended" id="iee0482b8c56e46a7a79daa123f351050_ComprehensiveIncomeChangesinAOCLDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_d33c1660-0653-4ff1-9c7c-2a0aafee60f5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward_8a81dfe1-a264-412d-9d18-b4d9036c8f29" xlink:href="lii-20210930.xsd#lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_d33c1660-0653-4ff1-9c7c-2a0aafee60f5" xlink:to="loc_lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward_8a81dfe1-a264-412d-9d18-b4d9036c8f29" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_c9d119a4-6614-47bb-9556-348a3008f954" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward_8a81dfe1-a264-412d-9d18-b4d9036c8f29" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_c9d119a4-6614-47bb-9556-348a3008f954" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_9770cb76-eb7d-465b-94e1-1a919686c7e2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward_8a81dfe1-a264-412d-9d18-b4d9036c8f29" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_9770cb76-eb7d-465b-94e1-1a919686c7e2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_07f18b28-b495-4582-866b-859ba88606a8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward_8a81dfe1-a264-412d-9d18-b4d9036c8f29" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_07f18b28-b495-4582-866b-859ba88606a8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_f0d7ea06-4826-4e6e-91f0-43725f326471" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward_8a81dfe1-a264-412d-9d18-b4d9036c8f29" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_f0d7ea06-4826-4e6e-91f0-43725f326471" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_7716013e-0a3c-4db1-bb02-0d34e1976804" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_660edeff-e16d-4b96-84f5-32f303f05327" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_d33c1660-0653-4ff1-9c7c-2a0aafee60f5" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_660edeff-e16d-4b96-84f5-32f303f05327" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_ebba689b-7b43-4962-9c15-c9b84591ff11" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_660edeff-e16d-4b96-84f5-32f303f05327" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_ebba689b-7b43-4962-9c15-c9b84591ff11" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_ebba689b-7b43-4962-9c15-c9b84591ff11_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_ebba689b-7b43-4962-9c15-c9b84591ff11" xlink:to="loc_us-gaap_EquityComponentDomain_ebba689b-7b43-4962-9c15-c9b84591ff11_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_3c64b224-defe-4081-82fa-e0a337abc23c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_ebba689b-7b43-4962-9c15-c9b84591ff11" xlink:to="loc_us-gaap_EquityComponentDomain_3c64b224-defe-4081-82fa-e0a337abc23c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_bb1b2c73-81b1-460f-8b9a-e9c05895dc73" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_3c64b224-defe-4081-82fa-e0a337abc23c" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_bb1b2c73-81b1-460f-8b9a-e9c05895dc73" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_710614d3-c139-416d-a333-7a2931ce2183" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_3c64b224-defe-4081-82fa-e0a337abc23c" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_710614d3-c139-416d-a333-7a2931ce2183" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_9c0b604c-4910-4424-be1f-b8fce83548d8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_3c64b224-defe-4081-82fa-e0a337abc23c" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_9c0b604c-4910-4424-be1f-b8fce83548d8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_bcd6831b-adc3-44eb-8b43-932797276305" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_3c64b224-defe-4081-82fa-e0a337abc23c" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_bcd6831b-adc3-44eb-8b43-932797276305" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentAttributableToNoncontrollingInterestMember_3b7d5c6a-c997-43f7-ba13-8cf74f2bd48d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentAttributableToNoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_3c64b224-defe-4081-82fa-e0a337abc23c" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentAttributableToNoncontrollingInterestMember_3b7d5c6a-c997-43f7-ba13-8cf74f2bd48d" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/FairValueMeasurementsOtherFairValueDisclosuresDetails" xlink:type="simple" xlink:href="lii-20210930.xsd#FairValueMeasurementsOtherFairValueDisclosuresDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/FairValueMeasurementsOtherFairValueDisclosuresDetails" xlink:type="extended" id="i56ae2ea8ba0f4aa2b79f9e098e031d9d_FairValueMeasurementsOtherFairValueDisclosuresDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_8f79505c-a889-47c5-9c82-20f186424bbd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_105fbfcb-1bfe-40f6-9ce1-7db0c78d73ee" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_8f79505c-a889-47c5-9c82-20f186424bbd" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_105fbfcb-1bfe-40f6-9ce1-7db0c78d73ee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFairValue_3fb74588-f8f4-419f-99a4-e05cc963e811" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_105fbfcb-1bfe-40f6-9ce1-7db0c78d73ee" xlink:to="loc_us-gaap_DebtInstrumentFairValue_3fb74588-f8f4-419f-99a4-e05cc963e811" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_e2338dba-72aa-4117-8b6d-3d04973e7505" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_8f79505c-a889-47c5-9c82-20f186424bbd" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_e2338dba-72aa-4117-8b6d-3d04973e7505" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e3c5b799-632f-44ac-9e14-57a5f5c60068" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_e2338dba-72aa-4117-8b6d-3d04973e7505" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e3c5b799-632f-44ac-9e14-57a5f5c60068" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e3c5b799-632f-44ac-9e14-57a5f5c60068_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e3c5b799-632f-44ac-9e14-57a5f5c60068" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_e3c5b799-632f-44ac-9e14-57a5f5c60068_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_667f83a6-819e-473e-a80e-4a1a1046d79f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_e3c5b799-632f-44ac-9e14-57a5f5c60068" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_667f83a6-819e-473e-a80e-4a1a1046d79f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_bbcbe896-41b8-4fc2-acad-8fc6d1c9541f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_667f83a6-819e-473e-a80e-4a1a1046d79f" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_bbcbe896-41b8-4fc2-acad-8fc6d1c9541f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_e1a7c66d-d41f-49f0-934e-77189a74c8b7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_e2338dba-72aa-4117-8b6d-3d04973e7505" xlink:to="loc_us-gaap_DebtInstrumentAxis_e1a7c66d-d41f-49f0-934e-77189a74c8b7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_e1a7c66d-d41f-49f0-934e-77189a74c8b7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_e1a7c66d-d41f-49f0-934e-77189a74c8b7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_e1a7c66d-d41f-49f0-934e-77189a74c8b7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_09fb900c-12d8-494f-971e-0710ef94409f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_e1a7c66d-d41f-49f0-934e-77189a74c8b7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_09fb900c-12d8-494f-971e-0710ef94409f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnsecuredDebtMember_f7121558-ca86-46bb-8d56-ca1595125a82" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnsecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_09fb900c-12d8-494f-971e-0710ef94409f" xlink:to="loc_us-gaap_UnsecuredDebtMember_f7121558-ca86-46bb-8d56-ca1595125a82" xlink:type="arc" order="0"/>
  </link:definitionLink>
</link:linkbase>
