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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2024 Workiva-->
<!--r:c695b7c9-d405-4a30-a4e7-dee8a847201e,g:c4352080-2bdb-40ef-93c5-f4443d958f92-->
<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/ConsolidatedStatementsofStockholdersDeficit" xlink:type="simple" xlink:href="lii-20240630.xsd#ConsolidatedStatementsofStockholdersDeficit"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/ConsolidatedStatementsofStockholdersDeficit" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_308db0ce-b7e6-4778-8c6e-850d22e88ace" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_3aaa89f0-22e7-45da-9a29-b775e7d72f28" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_308db0ce-b7e6-4778-8c6e-850d22e88ace" xlink:to="loc_us-gaap_StatementTable_3aaa89f0-22e7-45da-9a29-b775e7d72f28" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_e8798817-1ae5-4b8a-bc0d-c84bf04e7445" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_3aaa89f0-22e7-45da-9a29-b775e7d72f28" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_e8798817-1ae5-4b8a-bc0d-c84bf04e7445" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_e8798817-1ae5-4b8a-bc0d-c84bf04e7445_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_e8798817-1ae5-4b8a-bc0d-c84bf04e7445" xlink:to="loc_us-gaap_EquityComponentDomain_e8798817-1ae5-4b8a-bc0d-c84bf04e7445_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_2718d9e6-f66e-4c0c-b6ad-c605f14cf6aa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_e8798817-1ae5-4b8a-bc0d-c84bf04e7445" xlink:to="loc_us-gaap_EquityComponentDomain_2718d9e6-f66e-4c0c-b6ad-c605f14cf6aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_87a64c25-d5db-4894-b24c-ff198be31164" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_2718d9e6-f66e-4c0c-b6ad-c605f14cf6aa" xlink:to="loc_us-gaap_CommonStockMember_87a64c25-d5db-4894-b24c-ff198be31164" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_532c2fed-c188-43d2-b5af-dc4febef2a0e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_2718d9e6-f66e-4c0c-b6ad-c605f14cf6aa" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_532c2fed-c188-43d2-b5af-dc4febef2a0e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_87d8e179-cbf7-4555-ac76-3f807df176a3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_2718d9e6-f66e-4c0c-b6ad-c605f14cf6aa" xlink:to="loc_us-gaap_RetainedEarningsMember_87d8e179-cbf7-4555-ac76-3f807df176a3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_07733fed-3f5e-4fb8-bd26-0681e3d4bfb8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_2718d9e6-f66e-4c0c-b6ad-c605f14cf6aa" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_07733fed-3f5e-4fb8-bd26-0681e3d4bfb8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_8283037a-1586-4a5b-becf-b5793d1d9a96" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_2718d9e6-f66e-4c0c-b6ad-c605f14cf6aa" xlink:to="loc_us-gaap_TreasuryStockCommonMember_8283037a-1586-4a5b-becf-b5793d1d9a96" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_11b8d803-c9dd-4951-8b12-874d8ff3dcd7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_308db0ce-b7e6-4778-8c6e-850d22e88ace" xlink:to="loc_us-gaap_StockholdersEquity_11b8d803-c9dd-4951-8b12-874d8ff3dcd7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_6674bca1-1471-4568-9189-c6380d53708a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockCommonShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_308db0ce-b7e6-4778-8c6e-850d22e88ace" xlink:to="loc_us-gaap_TreasuryStockCommonShares_6674bca1-1471-4568-9189-c6380d53708a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_52863714-45dd-4cb6-ac4a-58f836f77cb8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_308db0ce-b7e6-4778-8c6e-850d22e88ace" xlink:to="loc_us-gaap_NetIncomeLoss_52863714-45dd-4cb6-ac4a-58f836f77cb8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_71f0fcd6-9a0e-4208-bd30-25b05f24fc5d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DividendsCommonStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_308db0ce-b7e6-4778-8c6e-850d22e88ace" xlink:to="loc_us-gaap_DividendsCommonStockCash_71f0fcd6-9a0e-4208-bd30-25b05f24fc5d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_79c4fb5a-8e0f-4b74-bc97-aba90ce2aa98" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_308db0ce-b7e6-4778-8c6e-850d22e88ace" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_79c4fb5a-8e0f-4b74-bc97-aba90ce2aa98" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_2a2e02c1-ce18-4bc0-a229-14bfe221d318" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_308db0ce-b7e6-4778-8c6e-850d22e88ace" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_2a2e02c1-ce18-4bc0-a229-14bfe221d318" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_9c4ad6f7-1eba-43ea-b032-5aeaef0b8f95" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_308db0ce-b7e6-4778-8c6e-850d22e88ace" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_9c4ad6f7-1eba-43ea-b032-5aeaef0b8f95" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax_18d0fb22-0971-47db-b2fe-5b08fc145f97" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_308db0ce-b7e6-4778-8c6e-850d22e88ace" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax_18d0fb22-0971-47db-b2fe-5b08fc145f97" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueTreasuryStockReissued_99879b2f-56d5-410b-8e46-4b6801a9efc7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueTreasuryStockReissued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_308db0ce-b7e6-4778-8c6e-850d22e88ace" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueTreasuryStockReissued_99879b2f-56d5-410b-8e46-4b6801a9efc7" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued_04450213-041e-430c-ba69-c141a9d5b336" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_308db0ce-b7e6-4778-8c6e-850d22e88ace" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued_04450213-041e-430c-ba69-c141a9d5b336" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_ae80767d-8249-4af7-acf7-b2cb8407f692" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_308db0ce-b7e6-4778-8c6e-850d22e88ace" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_ae80767d-8249-4af7-acf7-b2cb8407f692" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_ca144e3d-7cc7-4ff5-af25-f638bb73b1b2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_5e2ad5e3-0722-4aa9-96de-4d34e150a680" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockCommonShares"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/ReportableBusinessSegmentsSegmentDataDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#ReportableBusinessSegmentsSegmentDataDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/ReportableBusinessSegmentsSegmentDataDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_9dca39e0-4689-452b-ad7e-0cceaba7ada2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7eb2de79-1fee-46e3-8560-130de1768f1f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_9dca39e0-4689-452b-ad7e-0cceaba7ada2" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7eb2de79-1fee-46e3-8560-130de1768f1f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_79537328-99f0-4829-bc2b-4eb18f8af66c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7eb2de79-1fee-46e3-8560-130de1768f1f" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_79537328-99f0-4829-bc2b-4eb18f8af66c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_79537328-99f0-4829-bc2b-4eb18f8af66c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_79537328-99f0-4829-bc2b-4eb18f8af66c" xlink:to="loc_us-gaap_SegmentDomain_79537328-99f0-4829-bc2b-4eb18f8af66c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_ef15cee4-eaeb-4fbb-889e-cd9cf8d9d159" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_79537328-99f0-4829-bc2b-4eb18f8af66c" xlink:to="loc_us-gaap_SegmentDomain_ef15cee4-eaeb-4fbb-889e-cd9cf8d9d159" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ResidentialHeatingAndCoolingMember_3711bcdb-f475-45a7-a37a-5cdf29ef4bc7" xlink:href="lii-20240630.xsd#lii_ResidentialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ef15cee4-eaeb-4fbb-889e-cd9cf8d9d159" xlink:to="loc_lii_ResidentialHeatingAndCoolingMember_3711bcdb-f475-45a7-a37a-5cdf29ef4bc7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_f6255a67-8be9-4ff2-9d60-436e2348f5ad" xlink:href="lii-20240630.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ef15cee4-eaeb-4fbb-889e-cd9cf8d9d159" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_f6255a67-8be9-4ff2-9d60-436e2348f5ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateAndOtherMember_fe242a2a-858b-4f19-9c51-46c53b93c6dd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CorporateAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ef15cee4-eaeb-4fbb-889e-cd9cf8d9d159" xlink:to="loc_us-gaap_CorporateAndOtherMember_fe242a2a-858b-4f19-9c51-46c53b93c6dd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_2e28913e-00eb-4171-8cc7-663c3295659c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerSalesChannelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7eb2de79-1fee-46e3-8560-130de1768f1f" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_2e28913e-00eb-4171-8cc7-663c3295659c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_2e28913e-00eb-4171-8cc7-663c3295659c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_2e28913e-00eb-4171-8cc7-663c3295659c" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_2e28913e-00eb-4171-8cc7-663c3295659c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_e7bbf87a-12e4-4db5-8ca7-582aa19d09cd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_2e28913e-00eb-4171-8cc7-663c3295659c" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_e7bbf87a-12e4-4db5-8ca7-582aa19d09cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelDirectlyToConsumerMember_254e7051-bcbf-4f73-9438-b042e5f4e1ce" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SalesChannelDirectlyToConsumerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_e7bbf87a-12e4-4db5-8ca7-582aa19d09cd" xlink:to="loc_us-gaap_SalesChannelDirectlyToConsumerMember_254e7051-bcbf-4f73-9438-b042e5f4e1ce" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_e41a1f20-eea6-43a3-9fe4-7ea8fd324059" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_7eb2de79-1fee-46e3-8560-130de1768f1f" xlink:to="loc_srt_ProductOrServiceAxis_e41a1f20-eea6-43a3-9fe4-7ea8fd324059" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_e41a1f20-eea6-43a3-9fe4-7ea8fd324059_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_e41a1f20-eea6-43a3-9fe4-7ea8fd324059" xlink:to="loc_srt_ProductsAndServicesDomain_e41a1f20-eea6-43a3-9fe4-7ea8fd324059_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_057c38ae-020f-4a72-9736-f0676012a87e" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_e41a1f20-eea6-43a3-9fe4-7ea8fd324059" xlink:to="loc_srt_ProductsAndServicesDomain_057c38ae-020f-4a72-9736-f0676012a87e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_EquipmentSalesMember_ee4b56cb-463f-427c-9ff8-a5af059a8bf0" xlink:href="lii-20240630.xsd#lii_EquipmentSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_057c38ae-020f-4a72-9736-f0676012a87e" xlink:to="loc_lii_EquipmentSalesMember_ee4b56cb-463f-427c-9ff8-a5af059a8bf0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_825e8157-5802-4957-a1d3-50e0f1ebf643" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_9dca39e0-4689-452b-ad7e-0cceaba7ada2" xlink:to="loc_us-gaap_NumberOfReportableSegments_825e8157-5802-4957-a1d3-50e0f1ebf643" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract_d1724f0a-7d00-4264-9ed1-94f7b0091d09" xlink:href="lii-20240630.xsd#lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_9dca39e0-4689-452b-ad7e-0cceaba7ada2" xlink:to="loc_lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract_d1724f0a-7d00-4264-9ed1-94f7b0091d09" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_b2b77141-52a0-4b6a-bafc-abd02244f587" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract_d1724f0a-7d00-4264-9ed1-94f7b0091d09" xlink:to="loc_us-gaap_RevenuesAbstract_b2b77141-52a0-4b6a-bafc-abd02244f587" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_555b6bf5-9d49-4870-9c2b-ef825c083cf5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_b2b77141-52a0-4b6a-bafc-abd02244f587" xlink:to="loc_us-gaap_Revenues_555b6bf5-9d49-4870-9c2b-ef825c083cf5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationProfitLossAbstract_37f9664d-c52e-465f-bea0-1fdbc61a84f6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentReportingInformationProfitLossAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract_d1724f0a-7d00-4264-9ed1-94f7b0091d09" xlink:to="loc_us-gaap_SegmentReportingInformationProfitLossAbstract_37f9664d-c52e-465f-bea0-1fdbc61a84f6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_SegmentProfitAndLoss_e8da5c34-edcd-49c5-bb33-c35d6908ab04" xlink:href="lii-20240630.xsd#lii_SegmentProfitAndLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationProfitLossAbstract_37f9664d-c52e-465f-bea0-1fdbc61a84f6" xlink:to="loc_lii_SegmentProfitAndLoss_e8da5c34-edcd-49c5-bb33-c35d6908ab04" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_e90e03db-3dfa-4ea3-8e22-a105faa58902" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract_d1724f0a-7d00-4264-9ed1-94f7b0091d09" xlink:to="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_e90e03db-3dfa-4ea3-8e22-a105faa58902" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_GainLossOnPreviousAcquisition_dfd3a170-5611-4ec7-838b-217353c6800f" xlink:href="lii-20240630.xsd#lii_GainLossOnPreviousAcquisition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_e90e03db-3dfa-4ea3-8e22-a105faa58902" xlink:to="loc_lii_GainLossOnPreviousAcquisition_dfd3a170-5611-4ec7-838b-217353c6800f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_SegmentReportingReconcilingItemInLossesAndOtherExpensesFromSegmentToConsolidatedAmount_2a00dec0-81e5-4b3b-8907-a161d2d8bf5a" xlink:href="lii-20240630.xsd#lii_SegmentReportingReconcilingItemInLossesAndOtherExpensesFromSegmentToConsolidatedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_e90e03db-3dfa-4ea3-8e22-a105faa58902" xlink:to="loc_lii_SegmentReportingReconcilingItemInLossesAndOtherExpensesFromSegmentToConsolidatedAmount_2a00dec0-81e5-4b3b-8907-a161d2d8bf5a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_f4e6e094-ef06-478e-b432-f3afcebcb4de" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_e90e03db-3dfa-4ea3-8e22-a105faa58902" xlink:to="loc_us-gaap_OperatingIncomeLoss_f4e6e094-ef06-478e-b432-f3afcebcb4de" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/CommitmentsandContingenciesChangesinProductWarrantyLiabilitiesDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#CommitmentsandContingenciesChangesinProductWarrantyLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/CommitmentsandContingenciesChangesinProductWarrantyLiabilitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_3befba45-87fa-49d9-8b4b-67cb13908755" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_29c799d0-573f-46cb-a20c-0c6ee588c5fa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_3befba45-87fa-49d9-8b4b-67cb13908755" xlink:to="loc_us-gaap_LossContingenciesTable_29c799d0-573f-46cb-a20c-0c6ee588c5fa" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_77aad924-97dc-48c8-b9a0-f823b703a731" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_29c799d0-573f-46cb-a20c-0c6ee588c5fa" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_77aad924-97dc-48c8-b9a0-f823b703a731" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_77aad924-97dc-48c8-b9a0-f823b703a731_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_77aad924-97dc-48c8-b9a0-f823b703a731" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_77aad924-97dc-48c8-b9a0-f823b703a731_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_ee9dd010-6c02-4f73-a0c2-c0cc43669d82" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_77aad924-97dc-48c8-b9a0-f823b703a731" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_ee9dd010-6c02-4f73-a0c2-c0cc43669d82" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_37b19a89-6c9a-44e1-a6be-a99047f0f7ee" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_29c799d0-573f-46cb-a20c-0c6ee588c5fa" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_37b19a89-6c9a-44e1-a6be-a99047f0f7ee" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_37b19a89-6c9a-44e1-a6be-a99047f0f7ee_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_37b19a89-6c9a-44e1-a6be-a99047f0f7ee" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_37b19a89-6c9a-44e1-a6be-a99047f0f7ee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_72cdcb7f-6e4d-4740-a80a-32b0e7766c50" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_37b19a89-6c9a-44e1-a6be-a99047f0f7ee" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_72cdcb7f-6e4d-4740-a80a-32b0e7766c50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_256f3a63-92b2-41e7-a820-723724671ac6" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_LitigationCaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_29c799d0-573f-46cb-a20c-0c6ee588c5fa" xlink:to="loc_srt_LitigationCaseAxis_256f3a63-92b2-41e7-a820-723724671ac6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_256f3a63-92b2-41e7-a820-723724671ac6_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_256f3a63-92b2-41e7-a820-723724671ac6" xlink:to="loc_srt_LitigationCaseTypeDomain_256f3a63-92b2-41e7-a820-723724671ac6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_97d46abd-d2bc-4b07-b700-42586dde55a7" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_256f3a63-92b2-41e7-a820-723724671ac6" xlink:to="loc_srt_LitigationCaseTypeDomain_97d46abd-d2bc-4b07-b700-42586dde55a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusAxis_03ad5e5b-2a13-4e84-aa50-8d3214abb263" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LitigationStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_29c799d0-573f-46cb-a20c-0c6ee588c5fa" xlink:to="loc_us-gaap_LitigationStatusAxis_03ad5e5b-2a13-4e84-aa50-8d3214abb263" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_03ad5e5b-2a13-4e84-aa50-8d3214abb263_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LitigationStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LitigationStatusAxis_03ad5e5b-2a13-4e84-aa50-8d3214abb263" xlink:to="loc_us-gaap_LitigationStatusDomain_03ad5e5b-2a13-4e84-aa50-8d3214abb263_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_7429efa5-7b4d-4542-9a68-d86362dc0427" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LitigationStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LitigationStatusAxis_03ad5e5b-2a13-4e84-aa50-8d3214abb263" xlink:to="loc_us-gaap_LitigationStatusDomain_7429efa5-7b4d-4542-9a68-d86362dc0427" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_8a59c4a7-5249-4954-8283-af5693a10a90" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_29c799d0-573f-46cb-a20c-0c6ee588c5fa" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_8a59c4a7-5249-4954-8283-af5693a10a90" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_8a59c4a7-5249-4954-8283-af5693a10a90_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_8a59c4a7-5249-4954-8283-af5693a10a90" xlink:to="loc_us-gaap_LossContingencyNatureDomain_8a59c4a7-5249-4954-8283-af5693a10a90_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_83f36e1e-9ccd-49ee-9ad5-52697ffc802b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_8a59c4a7-5249-4954-8283-af5693a10a90" xlink:to="loc_us-gaap_LossContingencyNatureDomain_83f36e1e-9ccd-49ee-9ad5-52697ffc802b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_5b8c8022-cbe2-43a8-923a-e9ea5e40af4c" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_29c799d0-573f-46cb-a20c-0c6ee588c5fa" xlink:to="loc_srt_RangeAxis_5b8c8022-cbe2-43a8-923a-e9ea5e40af4c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_5b8c8022-cbe2-43a8-923a-e9ea5e40af4c_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_5b8c8022-cbe2-43a8-923a-e9ea5e40af4c" xlink:to="loc_srt_RangeMember_5b8c8022-cbe2-43a8-923a-e9ea5e40af4c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_118a0454-59f3-40f8-84a7-eaa22d96290e" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_5b8c8022-cbe2-43a8-923a-e9ea5e40af4c" xlink:to="loc_srt_RangeMember_118a0454-59f3-40f8-84a7-eaa22d96290e" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/CommitmentsandContingenciesNarrativeDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#CommitmentsandContingenciesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/CommitmentsandContingenciesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_c7e9d274-54bc-4b30-b267-743a3a1fb4cf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_0fb0ba9c-a706-4e16-ac74-822b77381aae" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_c7e9d274-54bc-4b30-b267-743a3a1fb4cf" xlink:to="loc_us-gaap_LossContingenciesTable_0fb0ba9c-a706-4e16-ac74-822b77381aae" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_34f62620-8bd9-4842-8dfe-65ce46c05696" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_0fb0ba9c-a706-4e16-ac74-822b77381aae" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_34f62620-8bd9-4842-8dfe-65ce46c05696" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_34f62620-8bd9-4842-8dfe-65ce46c05696_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_34f62620-8bd9-4842-8dfe-65ce46c05696" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_34f62620-8bd9-4842-8dfe-65ce46c05696_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_cc945cf1-3291-4373-8ec4-26497b0d5143" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_34f62620-8bd9-4842-8dfe-65ce46c05696" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_cc945cf1-3291-4373-8ec4-26497b0d5143" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_a122cbd1-40c1-4602-9d5d-0b2c4763bc3b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_0fb0ba9c-a706-4e16-ac74-822b77381aae" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_a122cbd1-40c1-4602-9d5d-0b2c4763bc3b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_a122cbd1-40c1-4602-9d5d-0b2c4763bc3b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_a122cbd1-40c1-4602-9d5d-0b2c4763bc3b" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_a122cbd1-40c1-4602-9d5d-0b2c4763bc3b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_63976e60-7d7c-4899-b2cd-bf4b19e69a63" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_a122cbd1-40c1-4602-9d5d-0b2c4763bc3b" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_63976e60-7d7c-4899-b2cd-bf4b19e69a63" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_04038bab-8555-4239-82ad-df2341a58553" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_LitigationCaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_0fb0ba9c-a706-4e16-ac74-822b77381aae" xlink:to="loc_srt_LitigationCaseAxis_04038bab-8555-4239-82ad-df2341a58553" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_04038bab-8555-4239-82ad-df2341a58553_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_04038bab-8555-4239-82ad-df2341a58553" xlink:to="loc_srt_LitigationCaseTypeDomain_04038bab-8555-4239-82ad-df2341a58553_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_036d2bdf-bbdc-4e56-8bbb-34434b157b3e" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_04038bab-8555-4239-82ad-df2341a58553" xlink:to="loc_srt_LitigationCaseTypeDomain_036d2bdf-bbdc-4e56-8bbb-34434b157b3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusAxis_c681832d-c90d-45ff-b258-1ddb54d1bd2f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LitigationStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_0fb0ba9c-a706-4e16-ac74-822b77381aae" xlink:to="loc_us-gaap_LitigationStatusAxis_c681832d-c90d-45ff-b258-1ddb54d1bd2f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_c681832d-c90d-45ff-b258-1ddb54d1bd2f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LitigationStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LitigationStatusAxis_c681832d-c90d-45ff-b258-1ddb54d1bd2f" xlink:to="loc_us-gaap_LitigationStatusDomain_c681832d-c90d-45ff-b258-1ddb54d1bd2f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_cbf501d2-f782-4575-b0cb-472d4534457e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LitigationStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LitigationStatusAxis_c681832d-c90d-45ff-b258-1ddb54d1bd2f" xlink:to="loc_us-gaap_LitigationStatusDomain_cbf501d2-f782-4575-b0cb-472d4534457e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_0c5c2a73-e9f1-4860-b880-64aef5eea5c7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_0fb0ba9c-a706-4e16-ac74-822b77381aae" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_0c5c2a73-e9f1-4860-b880-64aef5eea5c7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_0c5c2a73-e9f1-4860-b880-64aef5eea5c7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_0c5c2a73-e9f1-4860-b880-64aef5eea5c7" xlink:to="loc_us-gaap_LossContingencyNatureDomain_0c5c2a73-e9f1-4860-b880-64aef5eea5c7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_37ae4a3e-f718-4c7e-9aa2-c532855ab477" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LossContingencyNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_0c5c2a73-e9f1-4860-b880-64aef5eea5c7" xlink:to="loc_us-gaap_LossContingencyNatureDomain_37ae4a3e-f718-4c7e-9aa2-c532855ab477" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_e6ab7e9c-a927-450c-b523-817ae9d77426" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_0fb0ba9c-a706-4e16-ac74-822b77381aae" xlink:to="loc_srt_RangeAxis_e6ab7e9c-a927-450c-b523-817ae9d77426" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e6ab7e9c-a927-450c-b523-817ae9d77426_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_e6ab7e9c-a927-450c-b523-817ae9d77426" xlink:to="loc_srt_RangeMember_e6ab7e9c-a927-450c-b523-817ae9d77426_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_6ba2ddb3-3586-4c68-92a3-5f5bb44c6d32" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_e6ab7e9c-a927-450c-b523-817ae9d77426" xlink:to="loc_srt_RangeMember_6ba2ddb3-3586-4c68-92a3-5f5bb44c6d32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_OperatingLeaseRightOfUseAssetPercentageRelatedToLeasesOfRealEstate_5d7a0b1c-5cf8-4f1e-b425-66f2c9741653" xlink:href="lii-20240630.xsd#lii_OperatingLeaseRightOfUseAssetPercentageRelatedToLeasesOfRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_c7e9d274-54bc-4b30-b267-743a3a1fb4cf" xlink:to="loc_lii_OperatingLeaseRightOfUseAssetPercentageRelatedToLeasesOfRealEstate_5d7a0b1c-5cf8-4f1e-b425-66f2c9741653" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/RevenueRecognitionNarrativeDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#RevenueRecognitionNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/RevenueRecognitionNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_da432319-6f64-4a5c-8324-d344870f4cfd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_3cf5146e-0098-4174-b591-becd22a958be" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_da432319-6f64-4a5c-8324-d344870f4cfd" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_3cf5146e-0098-4174-b591-becd22a958be" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_44622c5b-6dda-4ec2-87c0-e35300d8ed3e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_3cf5146e-0098-4174-b591-becd22a958be" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_44622c5b-6dda-4ec2-87c0-e35300d8ed3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_44622c5b-6dda-4ec2-87c0-e35300d8ed3e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_44622c5b-6dda-4ec2-87c0-e35300d8ed3e" xlink:to="loc_us-gaap_SegmentDomain_44622c5b-6dda-4ec2-87c0-e35300d8ed3e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_ef8a1a7f-697c-4192-8143-3571be9e4b2c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_44622c5b-6dda-4ec2-87c0-e35300d8ed3e" xlink:to="loc_us-gaap_SegmentDomain_ef8a1a7f-697c-4192-8143-3571be9e4b2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ResidentialHeatingAndCoolingMember_e67436e6-007b-4875-9839-361d2035d4bb" xlink:href="lii-20240630.xsd#lii_ResidentialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ef8a1a7f-697c-4192-8143-3571be9e4b2c" xlink:to="loc_lii_ResidentialHeatingAndCoolingMember_e67436e6-007b-4875-9839-361d2035d4bb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_c7ca414a-23bd-4baf-a1b8-c6894dee3dd3" xlink:href="lii-20240630.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ef8a1a7f-697c-4192-8143-3571be9e4b2c" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_c7ca414a-23bd-4baf-a1b8-c6894dee3dd3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_7a43d9be-ab1b-4401-ba1b-1e92d79bdba6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerSalesChannelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_3cf5146e-0098-4174-b591-becd22a958be" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_7a43d9be-ab1b-4401-ba1b-1e92d79bdba6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_7a43d9be-ab1b-4401-ba1b-1e92d79bdba6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_7a43d9be-ab1b-4401-ba1b-1e92d79bdba6" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_7a43d9be-ab1b-4401-ba1b-1e92d79bdba6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_b47d345b-580d-418e-9e4c-e648941b2f1c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_7a43d9be-ab1b-4401-ba1b-1e92d79bdba6" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_b47d345b-580d-418e-9e4c-e648941b2f1c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelDirectlyToConsumerMember_817292b8-f1bf-44f8-86bf-a1ffbde1ea10" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SalesChannelDirectlyToConsumerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_b47d345b-580d-418e-9e4c-e648941b2f1c" xlink:to="loc_us-gaap_SalesChannelDirectlyToConsumerMember_817292b8-f1bf-44f8-86bf-a1ffbde1ea10" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_20aff4e3-78f0-4cd3-9002-bb7c782859d7" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_3cf5146e-0098-4174-b591-becd22a958be" xlink:to="loc_srt_ProductOrServiceAxis_20aff4e3-78f0-4cd3-9002-bb7c782859d7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_20aff4e3-78f0-4cd3-9002-bb7c782859d7_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_20aff4e3-78f0-4cd3-9002-bb7c782859d7" xlink:to="loc_srt_ProductsAndServicesDomain_20aff4e3-78f0-4cd3-9002-bb7c782859d7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_086fb520-4c0d-449e-8133-0e41b923e0ae" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_20aff4e3-78f0-4cd3-9002-bb7c782859d7" xlink:to="loc_srt_ProductsAndServicesDomain_086fb520-4c0d-449e-8133-0e41b923e0ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_EquipmentSalesMember_aece4a59-9393-4d64-8a29-455ab9a618fc" xlink:href="lii-20240630.xsd#lii_EquipmentSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_086fb520-4c0d-449e-8133-0e41b923e0ae" xlink:to="loc_lii_EquipmentSalesMember_aece4a59-9393-4d64-8a29-455ab9a618fc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_0c4d86f1-9cd1-4475-916d-ac8954b591b1" xlink:href="lii-20240630.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_086fb520-4c0d-449e-8133-0e41b923e0ae" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_0c4d86f1-9cd1-4475-916d-ac8954b591b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_d26158f7-25a7-46fa-bfdb-6d8ac73c2a87" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_da432319-6f64-4a5c-8324-d344870f4cfd" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_d26158f7-25a7-46fa-bfdb-6d8ac73c2a87" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_b7ddce86-beb2-4514-b5c6-8e0624b16fe8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_da432319-6f64-4a5c-8324-d344870f4cfd" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_b7ddce86-beb2-4514-b5c6-8e0624b16fe8" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/RevenueRecognitionRevenuebyBusinessSegmentbyGeographyDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#RevenueRecognitionRevenuebyBusinessSegmentbyGeographyDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/RevenueRecognitionRevenuebyBusinessSegmentbyGeographyDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_c56186f7-6c21-42e5-a6b8-812999175da2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_e855050b-d6cd-4e8b-afea-a74960e52a75" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_c56186f7-6c21-42e5-a6b8-812999175da2" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_e855050b-d6cd-4e8b-afea-a74960e52a75" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicDistributionAxis_01abe888-1ee5-4078-aef3-c97a74e6aa25" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GeographicDistributionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_e855050b-d6cd-4e8b-afea-a74960e52a75" xlink:to="loc_us-gaap_GeographicDistributionAxis_01abe888-1ee5-4078-aef3-c97a74e6aa25" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicDistributionDomain_01abe888-1ee5-4078-aef3-c97a74e6aa25_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GeographicDistributionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GeographicDistributionAxis_01abe888-1ee5-4078-aef3-c97a74e6aa25" xlink:to="loc_us-gaap_GeographicDistributionDomain_01abe888-1ee5-4078-aef3-c97a74e6aa25_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicDistributionDomain_f3be765d-2d8a-4d31-a2e0-aab76c5478f0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GeographicDistributionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GeographicDistributionAxis_01abe888-1ee5-4078-aef3-c97a74e6aa25" xlink:to="loc_us-gaap_GeographicDistributionDomain_f3be765d-2d8a-4d31-a2e0-aab76c5478f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_InternationalMember_98721e15-7a31-424f-b141-fa156116abe6" xlink:href="lii-20240630.xsd#lii_InternationalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GeographicDistributionDomain_f3be765d-2d8a-4d31-a2e0-aab76c5478f0" xlink:to="loc_lii_InternationalMember_98721e15-7a31-424f-b141-fa156116abe6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_CA_2f9ccad3-409c-4be5-b395-a09bac8ccb8d" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_CA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GeographicDistributionDomain_f3be765d-2d8a-4d31-a2e0-aab76c5478f0" xlink:to="loc_country_CA_2f9ccad3-409c-4be5-b395-a09bac8ccb8d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_7d6fcbcf-8df0-4220-8df4-1ed881d6ea7e" xlink:href="https://xbrl.sec.gov/country/2023/country-2023.xsd#country_US"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GeographicDistributionDomain_f3be765d-2d8a-4d31-a2e0-aab76c5478f0" xlink:to="loc_country_US_7d6fcbcf-8df0-4220-8df4-1ed881d6ea7e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_258ce148-bc3b-43be-959f-f18798c1eac6" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_e855050b-d6cd-4e8b-afea-a74960e52a75" xlink:to="loc_srt_ProductOrServiceAxis_258ce148-bc3b-43be-959f-f18798c1eac6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_258ce148-bc3b-43be-959f-f18798c1eac6_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_258ce148-bc3b-43be-959f-f18798c1eac6" xlink:to="loc_srt_ProductsAndServicesDomain_258ce148-bc3b-43be-959f-f18798c1eac6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_2d84d8c6-d06a-42c6-97ff-96fa0337f9cc" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_258ce148-bc3b-43be-959f-f18798c1eac6" xlink:to="loc_srt_ProductsAndServicesDomain_2d84d8c6-d06a-42c6-97ff-96fa0337f9cc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_EquipmentSalesMember_86ee3760-ad7e-4e30-a16a-ce371c2d412d" xlink:href="lii-20240630.xsd#lii_EquipmentSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_2d84d8c6-d06a-42c6-97ff-96fa0337f9cc" xlink:to="loc_lii_EquipmentSalesMember_86ee3760-ad7e-4e30-a16a-ce371c2d412d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_6e48a1a3-8aea-4b73-a042-fe7bb8bf4871" xlink:href="lii-20240630.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_2d84d8c6-d06a-42c6-97ff-96fa0337f9cc" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_6e48a1a3-8aea-4b73-a042-fe7bb8bf4871" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_b3531309-28ee-495d-91dd-28b8a142cb92" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_e855050b-d6cd-4e8b-afea-a74960e52a75" xlink:to="loc_srt_StatementGeographicalAxis_b3531309-28ee-495d-91dd-28b8a142cb92" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_b3531309-28ee-495d-91dd-28b8a142cb92_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_b3531309-28ee-495d-91dd-28b8a142cb92" xlink:to="loc_srt_SegmentGeographicalDomain_b3531309-28ee-495d-91dd-28b8a142cb92_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_80dcbe70-5d76-4c9e-85a6-789dbd4eb7be" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_b3531309-28ee-495d-91dd-28b8a142cb92" xlink:to="loc_srt_SegmentGeographicalDomain_80dcbe70-5d76-4c9e-85a6-789dbd4eb7be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_fe53345d-b4cf-4e74-b277-e5e0a37ee921" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerBasisOfPricingAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_e855050b-d6cd-4e8b-afea-a74960e52a75" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_fe53345d-b4cf-4e74-b277-e5e0a37ee921" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_fe53345d-b4cf-4e74-b277-e5e0a37ee921_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerBasisOfPricingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_fe53345d-b4cf-4e74-b277-e5e0a37ee921" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_fe53345d-b4cf-4e74-b277-e5e0a37ee921_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_7effd055-5114-4469-835b-65a0f4bd28d7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerBasisOfPricingDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_fe53345d-b4cf-4e74-b277-e5e0a37ee921" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_7effd055-5114-4469-835b-65a0f4bd28d7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelDirectlyToConsumerMember_2504d30d-a92c-4c01-80eb-afa270364f92" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SalesChannelDirectlyToConsumerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_7effd055-5114-4469-835b-65a0f4bd28d7" xlink:to="loc_us-gaap_SalesChannelDirectlyToConsumerMember_2504d30d-a92c-4c01-80eb-afa270364f92" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerDurationAxis_c59ea6dd-20bf-40ae-af83-d78e3b53045b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerDurationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_e855050b-d6cd-4e8b-afea-a74960e52a75" xlink:to="loc_us-gaap_ContractWithCustomerDurationAxis_c59ea6dd-20bf-40ae-af83-d78e3b53045b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerDurationDomain_c59ea6dd-20bf-40ae-af83-d78e3b53045b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerDurationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerDurationAxis_c59ea6dd-20bf-40ae-af83-d78e3b53045b" xlink:to="loc_us-gaap_ContractWithCustomerDurationDomain_c59ea6dd-20bf-40ae-af83-d78e3b53045b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerDurationDomain_30aaa373-d565-4157-bec8-c56e9c583263" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerDurationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerDurationAxis_c59ea6dd-20bf-40ae-af83-d78e3b53045b" xlink:to="loc_us-gaap_ContractWithCustomerDurationDomain_30aaa373-d565-4157-bec8-c56e9c583263" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_767cd661-bff5-445e-bd3d-a0e42828d17d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TimingOfTransferOfGoodOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_e855050b-d6cd-4e8b-afea-a74960e52a75" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_767cd661-bff5-445e-bd3d-a0e42828d17d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_767cd661-bff5-445e-bd3d-a0e42828d17d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_767cd661-bff5-445e-bd3d-a0e42828d17d" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_767cd661-bff5-445e-bd3d-a0e42828d17d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_94998784-4ca6-4e79-941a-7e7a502672ba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_767cd661-bff5-445e-bd3d-a0e42828d17d" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_94998784-4ca6-4e79-941a-7e7a502672ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_2240ff88-0c39-47b3-a85b-0b139a968a4f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerSalesChannelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_e855050b-d6cd-4e8b-afea-a74960e52a75" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_2240ff88-0c39-47b3-a85b-0b139a968a4f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_2240ff88-0c39-47b3-a85b-0b139a968a4f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_2240ff88-0c39-47b3-a85b-0b139a968a4f" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_2240ff88-0c39-47b3-a85b-0b139a968a4f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_d640bde0-4f9d-4e24-be7c-d49f61ba9972" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerSalesChannelDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelAxis_2240ff88-0c39-47b3-a85b-0b139a968a4f" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_d640bde0-4f9d-4e24-be7c-d49f61ba9972" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelDirectlyToConsumerMember_0418b039-5e6a-4ddc-85c0-90d40d90af71" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SalesChannelDirectlyToConsumerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ContractWithCustomerSalesChannelDomain_d640bde0-4f9d-4e24-be7c-d49f61ba9972" xlink:to="loc_us-gaap_SalesChannelDirectlyToConsumerMember_0418b039-5e6a-4ddc-85c0-90d40d90af71" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_d2cf1f88-d39c-4459-86bf-6eec10ed5a6f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_e855050b-d6cd-4e8b-afea-a74960e52a75" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_d2cf1f88-d39c-4459-86bf-6eec10ed5a6f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_d2cf1f88-d39c-4459-86bf-6eec10ed5a6f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_d2cf1f88-d39c-4459-86bf-6eec10ed5a6f" xlink:to="loc_us-gaap_SegmentDomain_d2cf1f88-d39c-4459-86bf-6eec10ed5a6f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_e6d94b35-85c4-42f0-934f-ddf359d9ebe8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_d2cf1f88-d39c-4459-86bf-6eec10ed5a6f" xlink:to="loc_us-gaap_SegmentDomain_e6d94b35-85c4-42f0-934f-ddf359d9ebe8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ResidentialHeatingAndCoolingMember_e2f6e3f8-6804-4c06-a0e8-403773608fc2" xlink:href="lii-20240630.xsd#lii_ResidentialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e6d94b35-85c4-42f0-934f-ddf359d9ebe8" xlink:to="loc_lii_ResidentialHeatingAndCoolingMember_e2f6e3f8-6804-4c06-a0e8-403773608fc2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_aff6aa50-9241-4dd6-99ff-4214a4dae190" xlink:href="lii-20240630.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e6d94b35-85c4-42f0-934f-ddf359d9ebe8" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_aff6aa50-9241-4dd6-99ff-4214a4dae190" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateAndOtherMember_53e7d11b-1691-4f93-805b-6e0f087fcb5b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CorporateAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e6d94b35-85c4-42f0-934f-ddf359d9ebe8" xlink:to="loc_us-gaap_CorporateAndOtherMember_53e7d11b-1691-4f93-805b-6e0f087fcb5b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_6fb4780a-e213-4015-9b89-f4b02bf53883" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_e855050b-d6cd-4e8b-afea-a74960e52a75" xlink:to="loc_srt_MajorCustomersAxis_6fb4780a-e213-4015-9b89-f4b02bf53883" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_6fb4780a-e213-4015-9b89-f4b02bf53883_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_6fb4780a-e213-4015-9b89-f4b02bf53883" xlink:to="loc_srt_NameOfMajorCustomerDomain_6fb4780a-e213-4015-9b89-f4b02bf53883_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_b2de047a-7492-40c7-a187-e477b0c4ced7" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_6fb4780a-e213-4015-9b89-f4b02bf53883" xlink:to="loc_srt_NameOfMajorCustomerDomain_b2de047a-7492-40c7-a187-e477b0c4ced7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_1aa1be1f-883d-40cd-8ca3-e68b80497649" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_c56186f7-6c21-42e5-a6b8-812999175da2" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_1aa1be1f-883d-40cd-8ca3-e68b80497649" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_f8b4be15-70ef-4207-82c8-44ba35213e2c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_c56186f7-6c21-42e5-a6b8-812999175da2" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_f8b4be15-70ef-4207-82c8-44ba35213e2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_b86bf66b-b0f7-4262-94c9-467de9d32d85" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_c56186f7-6c21-42e5-a6b8-812999175da2" xlink:to="loc_us-gaap_Revenues_b86bf66b-b0f7-4262-94c9-467de9d32d85" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/GoodwillDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#GoodwillDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/GoodwillDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_81bf2200-2e1a-4f23-b9be-f96854f3fb2f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_8bd0c875-dec7-46b7-84a8-a7af8e22f1c0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_81bf2200-2e1a-4f23-b9be-f96854f3fb2f" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_8bd0c875-dec7-46b7-84a8-a7af8e22f1c0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_3dbf14b3-a4e0-4c8a-b869-3627218c3675" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_8bd0c875-dec7-46b7-84a8-a7af8e22f1c0" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_3dbf14b3-a4e0-4c8a-b869-3627218c3675" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_3dbf14b3-a4e0-4c8a-b869-3627218c3675_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_3dbf14b3-a4e0-4c8a-b869-3627218c3675" xlink:to="loc_us-gaap_SegmentDomain_3dbf14b3-a4e0-4c8a-b869-3627218c3675_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_168859d0-e755-46ff-9267-9e32dc2db8ab" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_3dbf14b3-a4e0-4c8a-b869-3627218c3675" xlink:to="loc_us-gaap_SegmentDomain_168859d0-e755-46ff-9267-9e32dc2db8ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ResidentialHeatingAndCoolingMember_0890a257-eb72-49cf-9bac-8b8409552d0a" xlink:href="lii-20240630.xsd#lii_ResidentialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_168859d0-e755-46ff-9267-9e32dc2db8ab" xlink:to="loc_lii_ResidentialHeatingAndCoolingMember_0890a257-eb72-49cf-9bac-8b8409552d0a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_b59a4d97-7074-4334-8061-747ee6aece24" xlink:href="lii-20240630.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_168859d0-e755-46ff-9267-9e32dc2db8ab" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_b59a4d97-7074-4334-8061-747ee6aece24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_fafb9001-c837-4bf0-8e34-e533da1730d6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_8bd0c875-dec7-46b7-84a8-a7af8e22f1c0" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_fafb9001-c837-4bf0-8e34-e533da1730d6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_fafb9001-c837-4bf0-8e34-e533da1730d6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_fafb9001-c837-4bf0-8e34-e533da1730d6" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_fafb9001-c837-4bf0-8e34-e533da1730d6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6bf05fb1-1159-4c89-8be2-4b028eea4ea1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_fafb9001-c837-4bf0-8e34-e533da1730d6" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6bf05fb1-1159-4c89-8be2-4b028eea4ea1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_AESMember_988cb32e-37e4-45a6-b4f3-7eb2bcc6bdb4" xlink:href="lii-20240630.xsd#lii_AESMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_6bf05fb1-1159-4c89-8be2-4b028eea4ea1" xlink:to="loc_lii_AESMember_988cb32e-37e4-45a6-b4f3-7eb2bcc6bdb4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillRollForward_47617f09-7c4c-4db2-883c-1ae44f7efb9d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_81bf2200-2e1a-4f23-b9be-f96854f3fb2f" xlink:to="loc_us-gaap_GoodwillRollForward_47617f09-7c4c-4db2-883c-1ae44f7efb9d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_507877a1-87cb-4bdc-8df0-4ef429391751" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_47617f09-7c4c-4db2-883c-1ae44f7efb9d" xlink:to="loc_us-gaap_Goodwill_507877a1-87cb-4bdc-8df0-4ef429391751" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_c90001df-a033-4d6c-b782-bac949a9ddba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillPurchaseAccountingAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_47617f09-7c4c-4db2-883c-1ae44f7efb9d" xlink:to="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_c90001df-a033-4d6c-b782-bac949a9ddba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_b5d817f6-1019-47bd-b89b-e4a07f40b68c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Goodwill"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/DerivativesAOCLRelatedtoCashFlowHedgesDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#DerivativesAOCLRelatedtoCashFlowHedgesDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/DerivativesAOCLRelatedtoCashFlowHedgesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_e891cd3f-b4a8-4ef8-a5d9-f9115b75e984" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_e504ff87-612d-47d5-81b6-de6e65c2048f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_e891cd3f-b4a8-4ef8-a5d9-f9115b75e984" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_e504ff87-612d-47d5-81b6-de6e65c2048f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_35ae83fa-f0ef-4f8a-9875-910add3c2e0f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_e504ff87-612d-47d5-81b6-de6e65c2048f" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_35ae83fa-f0ef-4f8a-9875-910add3c2e0f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_35ae83fa-f0ef-4f8a-9875-910add3c2e0f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_35ae83fa-f0ef-4f8a-9875-910add3c2e0f" xlink:to="loc_us-gaap_HedgingRelationshipDomain_35ae83fa-f0ef-4f8a-9875-910add3c2e0f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_e686f956-ae63-470b-8093-474a0f36ca12" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_35ae83fa-f0ef-4f8a-9875-910add3c2e0f" xlink:to="loc_us-gaap_HedgingRelationshipDomain_e686f956-ae63-470b-8093-474a0f36ca12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_3316d058-d21a-4532-8d68-659d59deff5e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashFlowHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_e686f956-ae63-470b-8093-474a0f36ca12" xlink:to="loc_us-gaap_CashFlowHedgingMember_3316d058-d21a-4532-8d68-659d59deff5e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1_603a7807-67ea-4ecf-bb62-8ba272901614" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_e891cd3f-b4a8-4ef8-a5d9-f9115b75e984" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1_603a7807-67ea-4ecf-bb62-8ba272901614" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesProvisionBenefitForTax_fd9caaa1-2b06-4661-b41f-5e812b55a6f4" xlink:href="lii-20240630.xsd#lii_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesProvisionBenefitForTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_e891cd3f-b4a8-4ef8-a5d9-f9115b75e984" xlink:to="loc_lii_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesProvisionBenefitForTax_fd9caaa1-2b06-4661-b41f-5e812b55a6f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax_bf46c9b2-116d-486e-a1f3-b8195f35d7cd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_e891cd3f-b4a8-4ef8-a5d9-f9115b75e984" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax_bf46c9b2-116d-486e-a1f3-b8195f35d7cd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_005a15c1-f036-4e53-8d11-c4e1116880da" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_e891cd3f-b4a8-4ef8-a5d9-f9115b75e984" xlink:to="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_005a15c1-f036-4e53-8d11-c4e1116880da" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsOutstandingDebtObligationsDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#LinesofCreditandFinancingArrangementsOutstandingDebtObligationsDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsOutstandingDebtObligationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_f90f1f01-e806-4b76-927c-2f528fd5be96" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_335aad8b-dd77-4fcf-891f-677c46b603cf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_f90f1f01-e806-4b76-927c-2f528fd5be96" xlink:to="loc_us-gaap_DebtInstrumentTable_335aad8b-dd77-4fcf-891f-677c46b603cf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_8b743c32-92f3-4420-8f69-38986f384b3d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_335aad8b-dd77-4fcf-891f-677c46b603cf" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_8b743c32-92f3-4420-8f69-38986f384b3d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_8b743c32-92f3-4420-8f69-38986f384b3d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_8b743c32-92f3-4420-8f69-38986f384b3d" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_8b743c32-92f3-4420-8f69-38986f384b3d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_d33cc685-001b-4888-b9ff-16956ee90eaf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_8b743c32-92f3-4420-8f69-38986f384b3d" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_d33cc685-001b-4888-b9ff-16956ee90eaf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignLineOfCreditMember_6a19c605-c6e6-48b0-9e57-5f7a1315cb3c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ForeignLineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_d33cc685-001b-4888-b9ff-16956ee90eaf" xlink:to="loc_us-gaap_ForeignLineOfCreditMember_6a19c605-c6e6-48b0-9e57-5f7a1315cb3c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_348a77de-82d6-4e7d-8f7a-a5b1f1be5f0d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_335aad8b-dd77-4fcf-891f-677c46b603cf" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_348a77de-82d6-4e7d-8f7a-a5b1f1be5f0d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_348a77de-82d6-4e7d-8f7a-a5b1f1be5f0d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_348a77de-82d6-4e7d-8f7a-a5b1f1be5f0d" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_348a77de-82d6-4e7d-8f7a-a5b1f1be5f0d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_e0ed490e-a6f1-4368-8079-2f06fbd0b1c2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_348a77de-82d6-4e7d-8f7a-a5b1f1be5f0d" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_e0ed490e-a6f1-4368-8079-2f06fbd0b1c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_adb018e2-dc01-40df-90ac-fe93c7609c42" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_e0ed490e-a6f1-4368-8079-2f06fbd0b1c2" xlink:to="loc_us-gaap_SeniorNotesMember_adb018e2-dc01-40df-90ac-fe93c7609c42" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticLineOfCreditMember_6a210a57-f312-4464-be26-cc30309942ff" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DomesticLineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_e0ed490e-a6f1-4368-8079-2f06fbd0b1c2" xlink:to="loc_us-gaap_DomesticLineOfCreditMember_6a210a57-f312-4464-be26-cc30309942ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaper_9b41579c-dc56-4a03-a968-f39bb861756f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_f90f1f01-e806-4b76-927c-2f528fd5be96" xlink:to="loc_us-gaap_CommercialPaper_9b41579c-dc56-4a03-a968-f39bb861756f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrentAbstract_1d8a314f-8d71-4097-9400-ac4a41361592" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtCurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_f90f1f01-e806-4b76-927c-2f528fd5be96" xlink:to="loc_us-gaap_LongTermDebtCurrentAbstract_1d8a314f-8d71-4097-9400-ac4a41361592" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityCurrent_0711a9da-0900-46f0-b667-479d27debbbd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtCurrentAbstract_1d8a314f-8d71-4097-9400-ac4a41361592" xlink:to="loc_us-gaap_FinanceLeaseLiabilityCurrent_0711a9da-0900-46f0-b667-479d27debbbd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_9881ff9f-21ff-4563-b9a3-34949aa03f91" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtCurrentAbstract_1d8a314f-8d71-4097-9400-ac4a41361592" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_9881ff9f-21ff-4563-b9a3-34949aa03f91" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract_2337b169-19a1-40de-9a91-84b2c50fd79d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_f90f1f01-e806-4b76-927c-2f528fd5be96" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract_2337b169-19a1-40de-9a91-84b2c50fd79d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_c7550ff0-752a-4f0e-b631-394515f782a7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinanceLeaseLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract_2337b169-19a1-40de-9a91-84b2c50fd79d" xlink:to="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_c7550ff0-752a-4f0e-b631-394515f782a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_8bbc6247-b62b-4ae8-a180-e2d847ef38f1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract_2337b169-19a1-40de-9a91-84b2c50fd79d" xlink:to="loc_us-gaap_LongTermDebt_8bbc6247-b62b-4ae8-a180-e2d847ef38f1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNoncurrentGross_abdbe329-a4e9-4ce7-b7c8-725649811d05" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredFinanceCostsNoncurrentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract_2337b169-19a1-40de-9a91-84b2c50fd79d" xlink:to="loc_us-gaap_DeferredFinanceCostsNoncurrentGross_abdbe329-a4e9-4ce7-b7c8-725649811d05" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_63e32be3-2c5f-4448-9f44-05695b820d15" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract_2337b169-19a1-40de-9a91-84b2c50fd79d" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_63e32be3-2c5f-4448-9f44-05695b820d15" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtAndCapitalLeaseObligations_4aa15823-bd6c-41a4-8953-297f50a8d5ad" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtAndCapitalLeaseObligations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_f90f1f01-e806-4b76-927c-2f528fd5be96" xlink:to="loc_us-gaap_DebtAndCapitalLeaseObligations_4aa15823-bd6c-41a4-8953-297f50a8d5ad" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_92c070b6-0336-4b7a-938f-fec96791038e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_f90f1f01-e806-4b76-927c-2f528fd5be96" xlink:to="loc_us-gaap_ShortTermBorrowings_92c070b6-0336-4b7a-938f-fec96791038e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_7e66e52e-71f6-49a6-8bbf-1774bb02594f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_f90f1f01-e806-4b76-927c-2f528fd5be96" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_7e66e52e-71f6-49a6-8bbf-1774bb02594f" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsForeignObligationsDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#LinesofCreditandFinancingArrangementsForeignObligationsDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsForeignObligationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtLineItems_91d6f58b-10aa-4c7d-a056-de7a83fce31b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermDebtLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShortTermDebtTable_2c76e939-0d7a-4e2e-affd-3f67709b1721" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShortTermDebtTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortTermDebtLineItems_91d6f58b-10aa-4c7d-a056-de7a83fce31b" xlink:to="loc_us-gaap_ScheduleOfShortTermDebtTable_2c76e939-0d7a-4e2e-affd-3f67709b1721" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_a882fea9-6314-48eb-8d0a-e5b0fc68f009" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShortTermDebtTable_2c76e939-0d7a-4e2e-affd-3f67709b1721" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_a882fea9-6314-48eb-8d0a-e5b0fc68f009" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_a882fea9-6314-48eb-8d0a-e5b0fc68f009_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_a882fea9-6314-48eb-8d0a-e5b0fc68f009" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_a882fea9-6314-48eb-8d0a-e5b0fc68f009_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_71771dac-de01-4986-a248-b667794041f5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_a882fea9-6314-48eb-8d0a-e5b0fc68f009" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_71771dac-de01-4986-a248-b667794041f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignLineOfCreditMember_f4530816-7991-440c-9e53-a8b4d0a03a9a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ForeignLineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_71771dac-de01-4986-a248-b667794041f5" xlink:to="loc_us-gaap_ForeignLineOfCreditMember_f4530816-7991-440c-9e53-a8b4d0a03a9a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_be7fdf95-22c3-4654-bf40-82e29f6b7980" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShortTermBorrowings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_91d6f58b-10aa-4c7d-a056-de7a83fce31b" xlink:to="loc_us-gaap_ShortTermBorrowings_be7fdf95-22c3-4654-bf40-82e29f6b7980" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromShortTermDebt_95de59c5-280c-49f0-a116-5355e80e3f31" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromShortTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtLineItems_91d6f58b-10aa-4c7d-a056-de7a83fce31b" xlink:to="loc_us-gaap_ProceedsFromShortTermDebt_95de59c5-280c-49f0-a116-5355e80e3f31" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsCommercialPaperProgramDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#LinesofCreditandFinancingArrangementsCommercialPaperProgramDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsCommercialPaperProgramDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_0d368896-27f1-411a-8496-014caea0e8e5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_029c61a0-0a7d-481c-861f-9872209b4521" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_0d368896-27f1-411a-8496-014caea0e8e5" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_029c61a0-0a7d-481c-861f-9872209b4521" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_ceefe80e-0483-476b-9167-167d98d61cdf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_029c61a0-0a7d-481c-861f-9872209b4521" xlink:to="loc_us-gaap_DebtInstrumentAxis_ceefe80e-0483-476b-9167-167d98d61cdf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_ceefe80e-0483-476b-9167-167d98d61cdf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_ceefe80e-0483-476b-9167-167d98d61cdf" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_ceefe80e-0483-476b-9167-167d98d61cdf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_c4d561a8-b6fa-4b71-a351-0ed6b585f5eb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_ceefe80e-0483-476b-9167-167d98d61cdf" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_c4d561a8-b6fa-4b71-a351-0ed6b585f5eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_a319c332-056d-4bac-9162-42b3271c38d7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_c4d561a8-b6fa-4b71-a351-0ed6b585f5eb" xlink:to="loc_us-gaap_CommercialPaperMember_a319c332-056d-4bac-9162-42b3271c38d7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialPaperMaximumBorrowingCapacity_cad8c389-db3d-4621-b8db-8ca6b1c3221b" xlink:href="lii-20240630.xsd#lii_CommercialPaperMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_0d368896-27f1-411a-8496-014caea0e8e5" xlink:to="loc_lii_CommercialPaperMaximumBorrowingCapacity_cad8c389-db3d-4621-b8db-8ca6b1c3221b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_e800a81c-0fb7-42c0-83df-cc7f4124e4a5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_0d368896-27f1-411a-8496-014caea0e8e5" xlink:to="loc_us-gaap_DebtInstrumentTerm_e800a81c-0fb7-42c0-83df-cc7f4124e4a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaper_ef4b86c8-9a74-4c05-99ad-351ea2780ec1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_0d368896-27f1-411a-8496-014caea0e8e5" xlink:to="loc_us-gaap_CommercialPaper_ef4b86c8-9a74-4c05-99ad-351ea2780ec1" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsDomesticCreditFacilityDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#LinesofCreditandFinancingArrangementsDomesticCreditFacilityDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsDomesticCreditFacilityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_b4c3f5f6-7863-4656-9481-989102ed06db" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_64f17b92-02b9-48ae-9a8e-d656f71e0d31" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b4c3f5f6-7863-4656-9481-989102ed06db" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_64f17b92-02b9-48ae-9a8e-d656f71e0d31" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_bc89149a-0a68-4b8c-91a6-3fd04d9f5798" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_64f17b92-02b9-48ae-9a8e-d656f71e0d31" xlink:to="loc_us-gaap_DebtInstrumentAxis_bc89149a-0a68-4b8c-91a6-3fd04d9f5798" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_bc89149a-0a68-4b8c-91a6-3fd04d9f5798_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_bc89149a-0a68-4b8c-91a6-3fd04d9f5798" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_bc89149a-0a68-4b8c-91a6-3fd04d9f5798_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_cd018f63-5491-45fc-91da-935f17dc67db" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_bc89149a-0a68-4b8c-91a6-3fd04d9f5798" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_cd018f63-5491-45fc-91da-935f17dc67db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_1100423a-b3b2-499e-8662-836beb0ddfaf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_cd018f63-5491-45fc-91da-935f17dc67db" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_1100423a-b3b2-499e-8662-836beb0ddfaf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2025NotesMember_b0e580fc-645d-44b3-819d-2b13a518f97a" xlink:href="lii-20240630.xsd#lii_A2025NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_cd018f63-5491-45fc-91da-935f17dc67db" xlink:to="loc_lii_A2025NotesMember_b0e580fc-645d-44b3-819d-2b13a518f97a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2027NotesMember_902c2d7b-2117-46ac-8f80-00b1cc0299a9" xlink:href="lii-20240630.xsd#lii_A2027NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_cd018f63-5491-45fc-91da-935f17dc67db" xlink:to="loc_lii_A2027NotesMember_902c2d7b-2117-46ac-8f80-00b1cc0299a9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_2fcf845e-f947-4add-873f-7bedd6460fac" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_64f17b92-02b9-48ae-9a8e-d656f71e0d31" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_2fcf845e-f947-4add-873f-7bedd6460fac" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_2fcf845e-f947-4add-873f-7bedd6460fac_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_2fcf845e-f947-4add-873f-7bedd6460fac" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_2fcf845e-f947-4add-873f-7bedd6460fac_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_3f028b75-0d17-42c0-835f-10e2bce56829" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_2fcf845e-f947-4add-873f-7bedd6460fac" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_3f028b75-0d17-42c0-835f-10e2bce56829" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MediumTermNotesMember_a5bdfb96-c8a8-4020-8efa-422e5eb12e75" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MediumTermNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3f028b75-0d17-42c0-835f-10e2bce56829" xlink:to="loc_us-gaap_MediumTermNotesMember_a5bdfb96-c8a8-4020-8efa-422e5eb12e75" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_9675492e-37c8-4c85-b4be-4c15bd1ae915" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3f028b75-0d17-42c0-835f-10e2bce56829" xlink:to="loc_us-gaap_SeniorNotesMember_9675492e-37c8-4c85-b4be-4c15bd1ae915" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_bddde116-8471-4e37-9317-a8d398a415a8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_64f17b92-02b9-48ae-9a8e-d656f71e0d31" xlink:to="loc_us-gaap_CreditFacilityAxis_bddde116-8471-4e37-9317-a8d398a415a8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_bddde116-8471-4e37-9317-a8d398a415a8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_bddde116-8471-4e37-9317-a8d398a415a8" xlink:to="loc_us-gaap_CreditFacilityDomain_bddde116-8471-4e37-9317-a8d398a415a8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_f1dbf076-1fce-4221-9357-12c80cfbccc6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_bddde116-8471-4e37-9317-a8d398a415a8" xlink:to="loc_us-gaap_CreditFacilityDomain_f1dbf076-1fce-4221-9357-12c80cfbccc6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DomesticCreditFacilityMember_ec4716eb-2603-4f45-9cbf-4e40b808b0f1" xlink:href="lii-20240630.xsd#lii_DomesticCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_f1dbf076-1fce-4221-9357-12c80cfbccc6" xlink:to="loc_lii_DomesticCreditFacilityMember_ec4716eb-2603-4f45-9cbf-4e40b808b0f1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_c851ebfe-a64e-4cc1-8076-d50f8d30aa8f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_f1dbf076-1fce-4221-9357-12c80cfbccc6" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_c851ebfe-a64e-4cc1-8076-d50f8d30aa8f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_SubfacilityforSwinglineLoansMember_36386296-936b-4992-b2d1-0362a476eaa7" xlink:href="lii-20240630.xsd#lii_SubfacilityforSwinglineLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_f1dbf076-1fce-4221-9357-12c80cfbccc6" xlink:to="loc_lii_SubfacilityforSwinglineLoansMember_36386296-936b-4992-b2d1-0362a476eaa7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_473a4587-b13c-4cfb-8472-a6ec4a807b6c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b4c3f5f6-7863-4656-9481-989102ed06db" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_473a4587-b13c-4cfb-8472-a6ec4a807b6c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_043309b1-42d3-441f-b18d-3a92d34cebdb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b4c3f5f6-7863-4656-9481-989102ed06db" xlink:to="loc_us-gaap_LineOfCredit_043309b1-42d3-441f-b18d-3a92d34cebdb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_RevolvingCreditFacilityCommittedToStandByLettersOfCredit_421a194f-c8bf-47d0-88e3-bec8b47b077a" xlink:href="lii-20240630.xsd#lii_RevolvingCreditFacilityCommittedToStandByLettersOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b4c3f5f6-7863-4656-9481-989102ed06db" xlink:to="loc_lii_RevolvingCreditFacilityCommittedToStandByLettersOfCredit_421a194f-c8bf-47d0-88e3-bec8b47b077a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_3c35ba08-0076-491c-a6ad-94e98bbf8ed2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b4c3f5f6-7863-4656-9481-989102ed06db" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_3c35ba08-0076-491c-a6ad-94e98bbf8ed2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_ae79d02d-5153-4ecb-902b-2d0ae206c4ab" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b4c3f5f6-7863-4656-9481-989102ed06db" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_ae79d02d-5153-4ecb-902b-2d0ae206c4ab" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentNumberOfExtensionOptions_59c2a2a7-8770-4b26-a591-679b3362bf4c" xlink:href="lii-20240630.xsd#lii_DebtInstrumentNumberOfExtensionOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b4c3f5f6-7863-4656-9481-989102ed06db" xlink:to="loc_lii_DebtInstrumentNumberOfExtensionOptions_59c2a2a7-8770-4b26-a591-679b3362bf4c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentTermOfExtensionOptions_85eb736e-8b1e-4631-9c23-668691216908" xlink:href="lii-20240630.xsd#lii_DebtInstrumentTermOfExtensionOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b4c3f5f6-7863-4656-9481-989102ed06db" xlink:to="loc_lii_DebtInstrumentTermOfExtensionOptions_85eb736e-8b1e-4631-9c23-668691216908" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentCovenantNetLeverageRatio_588cf616-92f4-4e0c-9b84-7b5cde565586" xlink:href="lii-20240630.xsd#lii_DebtInstrumentCovenantNetLeverageRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b4c3f5f6-7863-4656-9481-989102ed06db" xlink:to="loc_lii_DebtInstrumentCovenantNetLeverageRatio_588cf616-92f4-4e0c-9b84-7b5cde565586" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentCovenantNetLeverageRatioFollowingMaterialAcquisition_9a5a718d-0549-4a50-bfe2-8ebd32227737" xlink:href="lii-20240630.xsd#lii_DebtInstrumentCovenantNetLeverageRatioFollowingMaterialAcquisition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b4c3f5f6-7863-4656-9481-989102ed06db" xlink:to="loc_lii_DebtInstrumentCovenantNetLeverageRatioFollowingMaterialAcquisition_9a5a718d-0549-4a50-bfe2-8ebd32227737" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization_66af0863-1dc9-4107-b7a1-cdfb07888381" xlink:href="lii-20240630.xsd#lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b4c3f5f6-7863-4656-9481-989102ed06db" xlink:to="loc_lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization_66af0863-1dc9-4107-b7a1-cdfb07888381" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentSeriesOfDebtNotes_b14b703d-643e-409d-be15-5a88fa408ee6" xlink:href="lii-20240630.xsd#lii_DebtInstrumentSeriesOfDebtNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b4c3f5f6-7863-4656-9481-989102ed06db" xlink:to="loc_lii_DebtInstrumentSeriesOfDebtNotes_b14b703d-643e-409d-be15-5a88fa408ee6" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_a2f49c4b-e701-4a2a-a942-d033a8982513" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_b4c3f5f6-7863-4656-9481-989102ed06db" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_a2f49c4b-e701-4a2a-a942-d033a8982513" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsWeightedAverageBorrowingRateDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#LinesofCreditandFinancingArrangementsWeightedAverageBorrowingRateDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsWeightedAverageBorrowingRateDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_38142980-4a07-4c44-a4ff-3dc5aca6ee09" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_bb5adb73-f5db-44d9-a816-e899344e15ac" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_38142980-4a07-4c44-a4ff-3dc5aca6ee09" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_bb5adb73-f5db-44d9-a816-e899344e15ac" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_a44f2cc5-bafc-412a-b1f4-8a413d92dbe2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_bb5adb73-f5db-44d9-a816-e899344e15ac" xlink:to="loc_us-gaap_DebtInstrumentAxis_a44f2cc5-bafc-412a-b1f4-8a413d92dbe2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_a44f2cc5-bafc-412a-b1f4-8a413d92dbe2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_a44f2cc5-bafc-412a-b1f4-8a413d92dbe2" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_a44f2cc5-bafc-412a-b1f4-8a413d92dbe2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_81c02027-ccd0-41b1-88a2-3e4a33627e1e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_a44f2cc5-bafc-412a-b1f4-8a413d92dbe2" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_81c02027-ccd0-41b1-88a2-3e4a33627e1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_0ceb3306-365f-43df-a34a-ec890742fb4d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_81c02027-ccd0-41b1-88a2-3e4a33627e1e" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_0ceb3306-365f-43df-a34a-ec890742fb4d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_959d8593-2a81-4082-b45f-5c0df7eaa82b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_81c02027-ccd0-41b1-88a2-3e4a33627e1e" xlink:to="loc_us-gaap_CommercialPaperMember_959d8593-2a81-4082-b45f-5c0df7eaa82b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_8706e015-44c4-4c14-87ad-f388f4941671" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_38142980-4a07-4c44-a4ff-3dc5aca6ee09" xlink:to="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_8706e015-44c4-4c14-87ad-f388f4941671" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsSeniorUnsecuredNotesDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#LinesofCreditandFinancingArrangementsSeniorUnsecuredNotesDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsSeniorUnsecuredNotesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_1f149463-a2e4-4a9f-9d4f-0498c221277d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_d966256b-d18a-4378-80d3-39997b753749" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1f149463-a2e4-4a9f-9d4f-0498c221277d" xlink:to="loc_us-gaap_DebtInstrumentTable_d966256b-d18a-4378-80d3-39997b753749" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_b7cb0f46-06f8-483d-8cb3-95afb0affcb8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d966256b-d18a-4378-80d3-39997b753749" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_b7cb0f46-06f8-483d-8cb3-95afb0affcb8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_b7cb0f46-06f8-483d-8cb3-95afb0affcb8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_b7cb0f46-06f8-483d-8cb3-95afb0affcb8" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_b7cb0f46-06f8-483d-8cb3-95afb0affcb8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_3300d0f8-b897-4253-92ea-911263f9dfc8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_b7cb0f46-06f8-483d-8cb3-95afb0affcb8" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_3300d0f8-b897-4253-92ea-911263f9dfc8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_53e3af12-323d-401a-979e-3684f160f95c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_3300d0f8-b897-4253-92ea-911263f9dfc8" xlink:to="loc_us-gaap_SeniorNotesMember_53e3af12-323d-401a-979e-3684f160f95c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_f4ff59dc-7dbe-4205-8a5e-ba05dc7b93bf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_d966256b-d18a-4378-80d3-39997b753749" xlink:to="loc_us-gaap_DebtInstrumentAxis_f4ff59dc-7dbe-4205-8a5e-ba05dc7b93bf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_f4ff59dc-7dbe-4205-8a5e-ba05dc7b93bf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_f4ff59dc-7dbe-4205-8a5e-ba05dc7b93bf" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_f4ff59dc-7dbe-4205-8a5e-ba05dc7b93bf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_c7055205-9c81-41f2-b1bc-5ca834ca44b7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_f4ff59dc-7dbe-4205-8a5e-ba05dc7b93bf" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_c7055205-9c81-41f2-b1bc-5ca834ca44b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2025NotesMember_e2be6e81-7b10-4887-8c17-987fb23edd25" xlink:href="lii-20240630.xsd#lii_A2025NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_c7055205-9c81-41f2-b1bc-5ca834ca44b7" xlink:to="loc_lii_A2025NotesMember_e2be6e81-7b10-4887-8c17-987fb23edd25" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2027NotesMember_d0b607aa-f5ca-4b2e-96dc-29b2f3069f30" xlink:href="lii-20240630.xsd#lii_A2027NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_c7055205-9c81-41f2-b1bc-5ca834ca44b7" xlink:to="loc_lii_A2027NotesMember_d0b607aa-f5ca-4b2e-96dc-29b2f3069f30" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2023NotesMember_230751cf-4f61-4012-8c2a-9e16a6f1f01a" xlink:href="lii-20240630.xsd#lii_A2023NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_c7055205-9c81-41f2-b1bc-5ca834ca44b7" xlink:to="loc_lii_A2023NotesMember_230751cf-4f61-4012-8c2a-9e16a6f1f01a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2028NotesMember_dfa34305-a697-4f01-bd82-f0bbe169d3af" xlink:href="lii-20240630.xsd#lii_A2028NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_c7055205-9c81-41f2-b1bc-5ca834ca44b7" xlink:to="loc_lii_A2028NotesMember_dfa34305-a697-4f01-bd82-f0bbe169d3af" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentSeriesOfDebtNotes_64592864-d859-49e8-ad32-15baaf58f31e" xlink:href="lii-20240630.xsd#lii_DebtInstrumentSeriesOfDebtNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1f149463-a2e4-4a9f-9d4f-0498c221277d" xlink:to="loc_lii_DebtInstrumentSeriesOfDebtNotes_64592864-d859-49e8-ad32-15baaf58f31e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_e29646f3-b155-46ad-80ec-a95ae9de1dc5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1f149463-a2e4-4a9f-9d4f-0498c221277d" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_e29646f3-b155-46ad-80ec-a95ae9de1dc5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_5cbc7568-48d4-4ada-a0ca-0ac1ac7ee910" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1f149463-a2e4-4a9f-9d4f-0498c221277d" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_5cbc7568-48d4-4ada-a0ca-0ac1ac7ee910" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization_70d04bb1-d727-4fa1-9fe7-fa57cc759aaf" xlink:href="lii-20240630.xsd#lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1f149463-a2e4-4a9f-9d4f-0498c221277d" xlink:to="loc_lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization_70d04bb1-d727-4fa1-9fe7-fa57cc759aaf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_PeriodForRescissionOfAcceleratedDebt_4401cafc-1ad0-46e8-a700-ba6f6a9e1ac3" xlink:href="lii-20240630.xsd#lii_PeriodForRescissionOfAcceleratedDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1f149463-a2e4-4a9f-9d4f-0498c221277d" xlink:to="loc_lii_PeriodForRescissionOfAcceleratedDebt_4401cafc-1ad0-46e8-a700-ba6f6a9e1ac3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_4ee7480d-3531-42ff-9b65-234e125fe06f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentRedemptionPricePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_1f149463-a2e4-4a9f-9d4f-0498c221277d" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_4ee7480d-3531-42ff-9b65-234e125fe06f" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/ComprehensiveIncomeLossReclassificationoutofAOCLDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#ComprehensiveIncomeLossReclassificationoutofAOCLDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/ComprehensiveIncomeLossReclassificationoutofAOCLDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_74e019bf-802c-4d9f-8914-b908dba1a809" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_ba44fac0-b39f-4ccc-ae4b-a427781ded62" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_74e019bf-802c-4d9f-8914-b908dba1a809" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_ba44fac0-b39f-4ccc-ae4b-a427781ded62" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_197085bd-8020-404e-b6de-d28d60e39d98" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_ba44fac0-b39f-4ccc-ae4b-a427781ded62" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_197085bd-8020-404e-b6de-d28d60e39d98" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_197085bd-8020-404e-b6de-d28d60e39d98_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_197085bd-8020-404e-b6de-d28d60e39d98" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_197085bd-8020-404e-b6de-d28d60e39d98_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_9edc88d0-4d1f-45e4-8492-cf89d67d46be" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_197085bd-8020-404e-b6de-d28d60e39d98" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_9edc88d0-4d1f-45e4-8492-cf89d67d46be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_7ec57e42-9e0d-46a4-a4ca-9e76744ef42b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_9edc88d0-4d1f-45e4-8492-cf89d67d46be" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_7ec57e42-9e0d-46a4-a4ca-9e76744ef42b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_d81bac3c-4a7b-4212-bae5-ee5714e55415" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_ba44fac0-b39f-4ccc-ae4b-a427781ded62" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_d81bac3c-4a7b-4212-bae5-ee5714e55415" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_d81bac3c-4a7b-4212-bae5-ee5714e55415_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_d81bac3c-4a7b-4212-bae5-ee5714e55415" xlink:to="loc_us-gaap_EquityComponentDomain_d81bac3c-4a7b-4212-bae5-ee5714e55415_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_f448f11d-c1bf-449d-b7d3-34300a5f3a23" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_d81bac3c-4a7b-4212-bae5-ee5714e55415" xlink:to="loc_us-gaap_EquityComponentDomain_f448f11d-c1bf-449d-b7d3-34300a5f3a23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_fc472fe5-3be5-4043-9094-9dcff22299d6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f448f11d-c1bf-449d-b7d3-34300a5f3a23" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_fc472fe5-3be5-4043-9094-9dcff22299d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_8dcd1b8e-be50-42bc-87a3-d720ac3962eb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f448f11d-c1bf-449d-b7d3-34300a5f3a23" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_8dcd1b8e-be50-42bc-87a3-d720ac3962eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_819a7148-93a8-4add-9cd5-a2800909e007" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f448f11d-c1bf-449d-b7d3-34300a5f3a23" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_819a7148-93a8-4add-9cd5-a2800909e007" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_26aab96d-2134-4159-80be-43b2894e0a57" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_ba44fac0-b39f-4ccc-ae4b-a427781ded62" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_26aab96d-2134-4159-80be-43b2894e0a57" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_26aab96d-2134-4159-80be-43b2894e0a57_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_26aab96d-2134-4159-80be-43b2894e0a57" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_26aab96d-2134-4159-80be-43b2894e0a57_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_7d07c880-b2df-449b-92dd-58ec17946649" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_26aab96d-2134-4159-80be-43b2894e0a57" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_7d07c880-b2df-449b-92dd-58ec17946649" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_df259cb2-03b3-4f7b-b52f-ebf790f5a511" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommodityContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_7d07c880-b2df-449b-92dd-58ec17946649" xlink:to="loc_us-gaap_CommodityContractMember_df259cb2-03b3-4f7b-b52f-ebf790f5a511" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_9d61b9df-69d0-4428-a06f-2e910922d281" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_74e019bf-802c-4d9f-8914-b908dba1a809" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_9d61b9df-69d0-4428-a06f-2e910922d281" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_08062b3a-eac3-44f2-8b6b-ca8cd950bebd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_74e019bf-802c-4d9f-8914-b908dba1a809" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_08062b3a-eac3-44f2-8b6b-ca8cd950bebd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_738f7069-314e-4f3a-ab85-2afb427a5eda" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_74e019bf-802c-4d9f-8914-b908dba1a809" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_738f7069-314e-4f3a-ab85-2afb427a5eda" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/ComprehensiveIncomeLossChangesinAOCLDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#ComprehensiveIncomeLossChangesinAOCLDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/ComprehensiveIncomeLossChangesinAOCLDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_f3d86be7-e454-47ed-b2e7-53671ec31f96" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_b8943ff5-f05e-4ba9-8498-131816b21955" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_f3d86be7-e454-47ed-b2e7-53671ec31f96" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_b8943ff5-f05e-4ba9-8498-131816b21955" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_48dd7e08-9e96-4a1d-89c5-bb0aea9dd632" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_b8943ff5-f05e-4ba9-8498-131816b21955" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_48dd7e08-9e96-4a1d-89c5-bb0aea9dd632" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_48dd7e08-9e96-4a1d-89c5-bb0aea9dd632_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_48dd7e08-9e96-4a1d-89c5-bb0aea9dd632" xlink:to="loc_us-gaap_EquityComponentDomain_48dd7e08-9e96-4a1d-89c5-bb0aea9dd632_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_89cea0fb-f465-43a4-bf31-ffc59c894dfa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_48dd7e08-9e96-4a1d-89c5-bb0aea9dd632" xlink:to="loc_us-gaap_EquityComponentDomain_89cea0fb-f465-43a4-bf31-ffc59c894dfa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_d6d58c4a-464a-453a-9ae5-dca2dd5d68f4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_89cea0fb-f465-43a4-bf31-ffc59c894dfa" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_d6d58c4a-464a-453a-9ae5-dca2dd5d68f4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_80d46554-c811-4c21-852b-3eef797fceb2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_89cea0fb-f465-43a4-bf31-ffc59c894dfa" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_80d46554-c811-4c21-852b-3eef797fceb2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_195b26c8-6c73-4d06-907b-0b1787603f27" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_89cea0fb-f465-43a4-bf31-ffc59c894dfa" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_195b26c8-6c73-4d06-907b-0b1787603f27" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_0d689361-2173-4ba0-b5f0-41ffe9dabc67" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_89cea0fb-f465-43a4-bf31-ffc59c894dfa" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_0d689361-2173-4ba0-b5f0-41ffe9dabc67" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentAttributableToNoncontrollingInterestMember_dcdf5c3a-76ce-4ed3-b007-40fd87e38de1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentAttributableToNoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_89cea0fb-f465-43a4-bf31-ffc59c894dfa" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentAttributableToNoncontrollingInterestMember_dcdf5c3a-76ce-4ed3-b007-40fd87e38de1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward_d381569a-9ece-4466-af82-cd574c38d005" xlink:href="lii-20240630.xsd#lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_f3d86be7-e454-47ed-b2e7-53671ec31f96" xlink:to="loc_lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward_d381569a-9ece-4466-af82-cd574c38d005" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_2b34e814-a9ee-4be1-b5e2-a2d9e98ff00a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward_d381569a-9ece-4466-af82-cd574c38d005" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_2b34e814-a9ee-4be1-b5e2-a2d9e98ff00a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_2efc9cb1-9c50-4db5-81b3-7cf41bb35bc7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward_d381569a-9ece-4466-af82-cd574c38d005" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_2efc9cb1-9c50-4db5-81b3-7cf41bb35bc7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_49484663-237f-4bcf-b0a9-3b23ef09ce4b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward_d381569a-9ece-4466-af82-cd574c38d005" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_49484663-237f-4bcf-b0a9-3b23ef09ce4b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_b15210b3-7af2-44f4-bc5a-0c9b60a22d13" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward_d381569a-9ece-4466-af82-cd574c38d005" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_b15210b3-7af2-44f4-bc5a-0c9b60a22d13" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_a73c4612-7c98-4acc-b5e1-e327156c2e79" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/FairValueMeasurementsOtherFairValueDisclosuresDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#FairValueMeasurementsOtherFairValueDisclosuresDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/FairValueMeasurementsOtherFairValueDisclosuresDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_15001f67-853b-4d0e-95ce-600afff1933c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_bd83e4e5-4452-46f2-882d-db82fe06082d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_15001f67-853b-4d0e-95ce-600afff1933c" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_bd83e4e5-4452-46f2-882d-db82fe06082d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_eaf3d39a-3bd5-49f8-9ec1-04eba0651bc5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_bd83e4e5-4452-46f2-882d-db82fe06082d" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_eaf3d39a-3bd5-49f8-9ec1-04eba0651bc5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_eaf3d39a-3bd5-49f8-9ec1-04eba0651bc5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_eaf3d39a-3bd5-49f8-9ec1-04eba0651bc5" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_eaf3d39a-3bd5-49f8-9ec1-04eba0651bc5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6136c8a7-cf35-441f-941b-ff2e1b5aaf06" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_eaf3d39a-3bd5-49f8-9ec1-04eba0651bc5" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6136c8a7-cf35-441f-941b-ff2e1b5aaf06" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_122bd5a3-8631-422f-8643-5fa49cd053e0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_6136c8a7-cf35-441f-941b-ff2e1b5aaf06" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_122bd5a3-8631-422f-8643-5fa49cd053e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_948ce444-7146-48f3-9430-aae81041af4b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_bd83e4e5-4452-46f2-882d-db82fe06082d" xlink:to="loc_us-gaap_DebtInstrumentAxis_948ce444-7146-48f3-9430-aae81041af4b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_948ce444-7146-48f3-9430-aae81041af4b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_948ce444-7146-48f3-9430-aae81041af4b" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_948ce444-7146-48f3-9430-aae81041af4b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_9f52f80e-6c07-4dd7-9808-f0a672146d6b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_948ce444-7146-48f3-9430-aae81041af4b" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_9f52f80e-6c07-4dd7-9808-f0a672146d6b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnsecuredDebtMember_82bbccb8-8f7d-48d3-9a68-bece02e5ec05" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnsecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_9f52f80e-6c07-4dd7-9808-f0a672146d6b" xlink:to="loc_us-gaap_UnsecuredDebtMember_82bbccb8-8f7d-48d3-9a68-bece02e5ec05" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_5b7d605d-1f27-46d9-8a08-dfaf7ecc1826" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_15001f67-853b-4d0e-95ce-600afff1933c" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_5b7d605d-1f27-46d9-8a08-dfaf7ecc1826" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFairValue_472cc86a-bb18-440f-8843-c2447df1739a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_5b7d605d-1f27-46d9-8a08-dfaf7ecc1826" xlink:to="loc_us-gaap_DebtInstrumentFairValue_472cc86a-bb18-440f-8843-c2447df1739a" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/BusinessCombinationsandAssetAcquisitionsDetails" xlink:type="simple" xlink:href="lii-20240630.xsd#BusinessCombinationsandAssetAcquisitionsDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/BusinessCombinationsandAssetAcquisitionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_5b4b3f3d-cc6f-4875-9e68-7020f15bf98e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_81998160-fa6d-4fbd-8919-326d5c45a7c0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b4b3f3d-cc6f-4875-9e68-7020f15bf98e" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_81998160-fa6d-4fbd-8919-326d5c45a7c0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_7e7db5fa-3cdf-445f-9348-44dd2e1cea72" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_81998160-fa6d-4fbd-8919-326d5c45a7c0" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_7e7db5fa-3cdf-445f-9348-44dd2e1cea72" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7e7db5fa-3cdf-445f-9348-44dd2e1cea72_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_7e7db5fa-3cdf-445f-9348-44dd2e1cea72" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7e7db5fa-3cdf-445f-9348-44dd2e1cea72_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_968f3580-e789-44d2-ba56-647279980997" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_7e7db5fa-3cdf-445f-9348-44dd2e1cea72" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_968f3580-e789-44d2-ba56-647279980997" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_AESMember_e9aa4083-9508-41e3-b311-fbcbb6ceae96" xlink:href="lii-20240630.xsd#lii_AESMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_968f3580-e789-44d2-ba56-647279980997" xlink:to="loc_lii_AESMember_e9aa4083-9508-41e3-b311-fbcbb6ceae96" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedExcludingIntangibleAssetsNet_285a91ea-ae3c-4ea8-8c52-a9213bce00b6" xlink:href="lii-20240630.xsd#lii_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedExcludingIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b4b3f3d-cc6f-4875-9e68-7020f15bf98e" xlink:to="loc_lii_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedExcludingIntangibleAssetsNet_285a91ea-ae3c-4ea8-8c52-a9213bce00b6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAssetsAndLiabilitiesAssumedExcludingIntangibleAssets_ce8fd17c-3f10-4b36-8013-52661d34d9a0" xlink:href="lii-20240630.xsd#lii_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAssetsAndLiabilitiesAssumedExcludingIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b4b3f3d-cc6f-4875-9e68-7020f15bf98e" xlink:to="loc_lii_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAssetsAndLiabilitiesAssumedExcludingIntangibleAssets_ce8fd17c-3f10-4b36-8013-52661d34d9a0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_8848d3bf-4be8-495d-8b07-203c17107470" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b4b3f3d-cc6f-4875-9e68-7020f15bf98e" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_8848d3bf-4be8-495d-8b07-203c17107470" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles_32cb1bc4-eaa0-43df-8db6-4cd1241f116d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b4b3f3d-cc6f-4875-9e68-7020f15bf98e" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles_32cb1bc4-eaa0-43df-8db6-4cd1241f116d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_57cf5eba-7d9e-4aff-8ecb-0efb549a1d28" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b4b3f3d-cc6f-4875-9e68-7020f15bf98e" xlink:to="loc_us-gaap_Goodwill_57cf5eba-7d9e-4aff-8ecb-0efb549a1d28" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_8b8c89c5-178e-4aae-91d4-5cde947904be" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillPurchaseAccountingAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b4b3f3d-cc6f-4875-9e68-7020f15bf98e" xlink:to="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_8b8c89c5-178e-4aae-91d4-5cde947904be" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_313afb29-a7a6-44ab-a49d-75d2d010f3f6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b4b3f3d-cc6f-4875-9e68-7020f15bf98e" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_313afb29-a7a6-44ab-a49d-75d2d010f3f6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentConsiderationTransferred_1706c38c-532a-4277-afbd-00fcc1668979" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentConsiderationTransferred"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5b4b3f3d-cc6f-4875-9e68-7020f15bf98e" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentConsiderationTransferred_1706c38c-532a-4277-afbd-00fcc1668979" xlink:type="arc" order="7"/>
  </link:definitionLink>
</link:linkbase>
