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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2024 Workiva-->
<!--r:8550225c-b345-4ae2-a89b-9da957cea664,g:488a4c39-9d15-4ef6-a6f8-d37b2b22dda0-->
<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-20240331.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_cc766f36-c1bd-41cb-a527-44237f91f708" 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_d2ccc268-3c48-4dcd-9035-b95c446d4c55" 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_cc766f36-c1bd-41cb-a527-44237f91f708" xlink:to="loc_us-gaap_StatementTable_d2ccc268-3c48-4dcd-9035-b95c446d4c55" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_7a335d66-4904-45ff-b143-3c4d406fe432" 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_d2ccc268-3c48-4dcd-9035-b95c446d4c55" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_7a335d66-4904-45ff-b143-3c4d406fe432" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_7a335d66-4904-45ff-b143-3c4d406fe432_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_7a335d66-4904-45ff-b143-3c4d406fe432" xlink:to="loc_us-gaap_EquityComponentDomain_7a335d66-4904-45ff-b143-3c4d406fe432_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_3b5368b6-5065-4e3a-a4d2-d614b9aa3e98" 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_7a335d66-4904-45ff-b143-3c4d406fe432" xlink:to="loc_us-gaap_EquityComponentDomain_3b5368b6-5065-4e3a-a4d2-d614b9aa3e98" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_35291541-8994-434c-93be-f3c251c58de8" 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_3b5368b6-5065-4e3a-a4d2-d614b9aa3e98" xlink:to="loc_us-gaap_CommonStockMember_35291541-8994-434c-93be-f3c251c58de8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_f597fc1f-746a-4c5c-b092-7857c62ddab5" 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_3b5368b6-5065-4e3a-a4d2-d614b9aa3e98" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_f597fc1f-746a-4c5c-b092-7857c62ddab5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_05465d9e-fe46-4d6e-9ced-d613d7074cbe" 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_3b5368b6-5065-4e3a-a4d2-d614b9aa3e98" xlink:to="loc_us-gaap_RetainedEarningsMember_05465d9e-fe46-4d6e-9ced-d613d7074cbe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_cb6c0f41-7a8a-4ff1-b723-87904708e275" 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_3b5368b6-5065-4e3a-a4d2-d614b9aa3e98" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_cb6c0f41-7a8a-4ff1-b723-87904708e275" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_b2bab7af-7582-4b46-8e64-7e45920d167f" 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_3b5368b6-5065-4e3a-a4d2-d614b9aa3e98" xlink:to="loc_us-gaap_TreasuryStockCommonMember_b2bab7af-7582-4b46-8e64-7e45920d167f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_5e998b99-c588-47ae-b730-7671813054c4" 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_cc766f36-c1bd-41cb-a527-44237f91f708" xlink:to="loc_us-gaap_StockholdersEquity_5e998b99-c588-47ae-b730-7671813054c4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_ed8a3957-1c67-43c7-a478-a966e7b12262" 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_cc766f36-c1bd-41cb-a527-44237f91f708" xlink:to="loc_us-gaap_TreasuryStockCommonShares_ed8a3957-1c67-43c7-a478-a966e7b12262" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_de99f7ae-4a80-43f2-a41a-224691942292" 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_cc766f36-c1bd-41cb-a527-44237f91f708" xlink:to="loc_us-gaap_NetIncomeLoss_de99f7ae-4a80-43f2-a41a-224691942292" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_e92a0bc3-f7ee-4033-9478-cf84e88fe03e" 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_cc766f36-c1bd-41cb-a527-44237f91f708" xlink:to="loc_us-gaap_DividendsCommonStockCash_e92a0bc3-f7ee-4033-9478-cf84e88fe03e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_67f83a3e-1ae3-41dd-8c38-dfd645f0e7ae" 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_cc766f36-c1bd-41cb-a527-44237f91f708" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_67f83a3e-1ae3-41dd-8c38-dfd645f0e7ae" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_9f98c560-dcf2-400a-8e10-c6e698f4ee25" 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_cc766f36-c1bd-41cb-a527-44237f91f708" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_9f98c560-dcf2-400a-8e10-c6e698f4ee25" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_74696807-cdf9-4978-bbe5-4dbd5bfaf4f9" 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_cc766f36-c1bd-41cb-a527-44237f91f708" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_74696807-cdf9-4978-bbe5-4dbd5bfaf4f9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax_e8f92f25-a38c-4916-9666-ee30cd64aba0" 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_cc766f36-c1bd-41cb-a527-44237f91f708" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAfterTax_e8f92f25-a38c-4916-9666-ee30cd64aba0" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueTreasuryStockReissued_c1fea403-8852-45a9-bdeb-d86b5c7203f2" 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_cc766f36-c1bd-41cb-a527-44237f91f708" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueTreasuryStockReissued_c1fea403-8852-45a9-bdeb-d86b5c7203f2" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued_76ee9784-03b4-4254-ba6c-0623885f7935" 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_cc766f36-c1bd-41cb-a527-44237f91f708" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesTreasuryStockReissued_76ee9784-03b4-4254-ba6c-0623885f7935" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_74dd28d3-a1b0-4f22-9249-4032dc52b2e2" 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_cc766f36-c1bd-41cb-a527-44237f91f708" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_74dd28d3-a1b0-4f22-9249-4032dc52b2e2" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_fdf74bc5-d2cf-44c1-a9a7-7ba5a9a02f1b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockSharesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_cc766f36-c1bd-41cb-a527-44237f91f708" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_fdf74bc5-d2cf-44c1-a9a7-7ba5a9a02f1b" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_d7985ae6-6028-489f-9b1b-dc5eb55b743e" 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_153ba3b0-67eb-40d0-94bb-975b6eebf895" 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-20240331.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_d7139437-6ce2-4775-8426-2f52e67e1a30" 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_e8d40642-7881-491e-bfc4-67fe1465d610" 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_d7139437-6ce2-4775-8426-2f52e67e1a30" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_e8d40642-7881-491e-bfc4-67fe1465d610" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_57ac413e-c4aa-4263-ac22-8eb5a6704cf6" 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_e8d40642-7881-491e-bfc4-67fe1465d610" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_57ac413e-c4aa-4263-ac22-8eb5a6704cf6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_57ac413e-c4aa-4263-ac22-8eb5a6704cf6_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_57ac413e-c4aa-4263-ac22-8eb5a6704cf6" xlink:to="loc_us-gaap_SegmentDomain_57ac413e-c4aa-4263-ac22-8eb5a6704cf6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_e2656fdc-9db1-4015-b2f0-fbae4d0ae544" 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_57ac413e-c4aa-4263-ac22-8eb5a6704cf6" xlink:to="loc_us-gaap_SegmentDomain_e2656fdc-9db1-4015-b2f0-fbae4d0ae544" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ResidentialHeatingAndCoolingMember_28eeeff2-cbb3-4d86-bd8f-c3d74b60411b" xlink:href="lii-20240331.xsd#lii_ResidentialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e2656fdc-9db1-4015-b2f0-fbae4d0ae544" xlink:to="loc_lii_ResidentialHeatingAndCoolingMember_28eeeff2-cbb3-4d86-bd8f-c3d74b60411b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_2c69a1fa-1abe-45af-a2b6-e8995df7fa38" xlink:href="lii-20240331.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e2656fdc-9db1-4015-b2f0-fbae4d0ae544" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_2c69a1fa-1abe-45af-a2b6-e8995df7fa38" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateAndOtherMember_4eecb70f-ffbc-4cf4-8b5b-bae90cd905e4" 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_e2656fdc-9db1-4015-b2f0-fbae4d0ae544" xlink:to="loc_us-gaap_CorporateAndOtherMember_4eecb70f-ffbc-4cf4-8b5b-bae90cd905e4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_de9bce75-0485-4f65-aeda-088e5c87db5a" 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_e8d40642-7881-491e-bfc4-67fe1465d610" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_de9bce75-0485-4f65-aeda-088e5c87db5a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_de9bce75-0485-4f65-aeda-088e5c87db5a_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_de9bce75-0485-4f65-aeda-088e5c87db5a" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_de9bce75-0485-4f65-aeda-088e5c87db5a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_ed290605-c090-4756-a378-d60b083a9b3d" 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_de9bce75-0485-4f65-aeda-088e5c87db5a" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_ed290605-c090-4756-a378-d60b083a9b3d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelDirectlyToConsumerMember_77cfab36-a204-4b06-858f-65201ee05d55" 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_ed290605-c090-4756-a378-d60b083a9b3d" xlink:to="loc_us-gaap_SalesChannelDirectlyToConsumerMember_77cfab36-a204-4b06-858f-65201ee05d55" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_fa5e9996-7b91-4aab-aa4e-b4e29ae10752" 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_e8d40642-7881-491e-bfc4-67fe1465d610" xlink:to="loc_srt_ProductOrServiceAxis_fa5e9996-7b91-4aab-aa4e-b4e29ae10752" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_fa5e9996-7b91-4aab-aa4e-b4e29ae10752_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_fa5e9996-7b91-4aab-aa4e-b4e29ae10752" xlink:to="loc_srt_ProductsAndServicesDomain_fa5e9996-7b91-4aab-aa4e-b4e29ae10752_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_733a9ffd-14d7-4380-a1fe-c95be8d1498b" 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_fa5e9996-7b91-4aab-aa4e-b4e29ae10752" xlink:to="loc_srt_ProductsAndServicesDomain_733a9ffd-14d7-4380-a1fe-c95be8d1498b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_EquipmentSalesMember_5deb689b-73c7-4ab7-a237-11fc6f32b2f8" xlink:href="lii-20240331.xsd#lii_EquipmentSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_733a9ffd-14d7-4380-a1fe-c95be8d1498b" xlink:to="loc_lii_EquipmentSalesMember_5deb689b-73c7-4ab7-a237-11fc6f32b2f8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_0120c23f-8220-4826-a9ce-cf80d97eac6d" 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_d7139437-6ce2-4775-8426-2f52e67e1a30" xlink:to="loc_us-gaap_NumberOfReportableSegments_0120c23f-8220-4826-a9ce-cf80d97eac6d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract_3567c54a-0685-465e-881a-f65c1099fa49" xlink:href="lii-20240331.xsd#lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_d7139437-6ce2-4775-8426-2f52e67e1a30" xlink:to="loc_lii_NetSalesSegmentProfitLossByBusinessSegmentAndReconciliationOfSegmentProfitLossToIncomeFromContinuingOperationsBeforeIncomeTaxesAbstract_3567c54a-0685-465e-881a-f65c1099fa49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_1737f693-a5e2-4ae8-95c7-c32c4c5a7f0d" 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_3567c54a-0685-465e-881a-f65c1099fa49" xlink:to="loc_us-gaap_RevenuesAbstract_1737f693-a5e2-4ae8-95c7-c32c4c5a7f0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_3cc3619e-9f18-4c82-a9f3-b83f24e5a9f5" 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_1737f693-a5e2-4ae8-95c7-c32c4c5a7f0d" xlink:to="loc_us-gaap_Revenues_3cc3619e-9f18-4c82-a9f3-b83f24e5a9f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationProfitLossAbstract_1a2f461f-89d5-4061-9754-66040f4e1549" 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_3567c54a-0685-465e-881a-f65c1099fa49" xlink:to="loc_us-gaap_SegmentReportingInformationProfitLossAbstract_1a2f461f-89d5-4061-9754-66040f4e1549" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_SegmentProfitAndLoss_c53ed04a-a12a-4f4a-b891-19a30c7aa9d8" xlink:href="lii-20240331.xsd#lii_SegmentProfitAndLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationProfitLossAbstract_1a2f461f-89d5-4061-9754-66040f4e1549" xlink:to="loc_lii_SegmentProfitAndLoss_c53ed04a-a12a-4f4a-b891-19a30c7aa9d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_c7d0748c-27ec-482f-a9f2-770d4f82e512" 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_3567c54a-0685-465e-881a-f65c1099fa49" xlink:to="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_c7d0748c-27ec-482f-a9f2-770d4f82e512" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_SegmentReportingReconcilingItemInLossesAndOtherExpensesFromSegmentToConsolidatedAmount_628d1ca3-4481-42b4-875e-b30d2ec38452" xlink:href="lii-20240331.xsd#lii_SegmentReportingReconcilingItemInLossesAndOtherExpensesFromSegmentToConsolidatedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedAbstract_c7d0748c-27ec-482f-a9f2-770d4f82e512" xlink:to="loc_lii_SegmentReportingReconcilingItemInLossesAndOtherExpensesFromSegmentToConsolidatedAmount_628d1ca3-4481-42b4-875e-b30d2ec38452" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_f4c944ea-772f-4208-a812-536d8a81e596" 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_c7d0748c-27ec-482f-a9f2-770d4f82e512" xlink:to="loc_us-gaap_OperatingIncomeLoss_f4c944ea-772f-4208-a812-536d8a81e596" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/CommitmentsandContingenciesChangesinProductWarrantyLiabilitiesDetails" xlink:type="simple" xlink:href="lii-20240331.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_7001f20d-0bdd-428f-8437-af45a36c2d13" 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_dabd36ed-3a92-43b8-9848-30a7ab1d8544" 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_7001f20d-0bdd-428f-8437-af45a36c2d13" xlink:to="loc_us-gaap_LossContingenciesTable_dabd36ed-3a92-43b8-9848-30a7ab1d8544" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_305cdb0d-3c71-4d7b-9112-f3062fe1da25" 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_dabd36ed-3a92-43b8-9848-30a7ab1d8544" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_305cdb0d-3c71-4d7b-9112-f3062fe1da25" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_305cdb0d-3c71-4d7b-9112-f3062fe1da25_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_305cdb0d-3c71-4d7b-9112-f3062fe1da25" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_305cdb0d-3c71-4d7b-9112-f3062fe1da25_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_cbfdabff-12df-41a8-b9d5-fdc990d10f5a" 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_305cdb0d-3c71-4d7b-9112-f3062fe1da25" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_cbfdabff-12df-41a8-b9d5-fdc990d10f5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_022ba65b-5d4f-425d-823f-b213b9e3b5b4" 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_dabd36ed-3a92-43b8-9848-30a7ab1d8544" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_022ba65b-5d4f-425d-823f-b213b9e3b5b4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_022ba65b-5d4f-425d-823f-b213b9e3b5b4_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_022ba65b-5d4f-425d-823f-b213b9e3b5b4" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_022ba65b-5d4f-425d-823f-b213b9e3b5b4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_7457c949-2229-4b19-b9d3-848a4c745660" 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_022ba65b-5d4f-425d-823f-b213b9e3b5b4" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_7457c949-2229-4b19-b9d3-848a4c745660" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_6bd32760-3ba4-4579-9114-55bcf51f082c" 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_dabd36ed-3a92-43b8-9848-30a7ab1d8544" xlink:to="loc_srt_LitigationCaseAxis_6bd32760-3ba4-4579-9114-55bcf51f082c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_6bd32760-3ba4-4579-9114-55bcf51f082c_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_6bd32760-3ba4-4579-9114-55bcf51f082c" xlink:to="loc_srt_LitigationCaseTypeDomain_6bd32760-3ba4-4579-9114-55bcf51f082c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_72388c6d-cf4a-45a4-bf28-dd112957b28d" 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_6bd32760-3ba4-4579-9114-55bcf51f082c" xlink:to="loc_srt_LitigationCaseTypeDomain_72388c6d-cf4a-45a4-bf28-dd112957b28d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusAxis_76dbd898-acd6-4cb0-8841-6db4825f961b" 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_dabd36ed-3a92-43b8-9848-30a7ab1d8544" xlink:to="loc_us-gaap_LitigationStatusAxis_76dbd898-acd6-4cb0-8841-6db4825f961b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_76dbd898-acd6-4cb0-8841-6db4825f961b_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_76dbd898-acd6-4cb0-8841-6db4825f961b" xlink:to="loc_us-gaap_LitigationStatusDomain_76dbd898-acd6-4cb0-8841-6db4825f961b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_2f708f17-af69-46ef-9950-0f90c7cd669a" 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_76dbd898-acd6-4cb0-8841-6db4825f961b" xlink:to="loc_us-gaap_LitigationStatusDomain_2f708f17-af69-46ef-9950-0f90c7cd669a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_9602f0a1-441e-4346-ab74-ec69ca571ad2" 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_dabd36ed-3a92-43b8-9848-30a7ab1d8544" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_9602f0a1-441e-4346-ab74-ec69ca571ad2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_9602f0a1-441e-4346-ab74-ec69ca571ad2_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_9602f0a1-441e-4346-ab74-ec69ca571ad2" xlink:to="loc_us-gaap_LossContingencyNatureDomain_9602f0a1-441e-4346-ab74-ec69ca571ad2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_f7fe00b0-96ce-444f-bc58-858df60f3861" 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_9602f0a1-441e-4346-ab74-ec69ca571ad2" xlink:to="loc_us-gaap_LossContingencyNatureDomain_f7fe00b0-96ce-444f-bc58-858df60f3861" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_2a7300ab-4653-491e-8606-02aa6c20b506" 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_dabd36ed-3a92-43b8-9848-30a7ab1d8544" xlink:to="loc_srt_RangeAxis_2a7300ab-4653-491e-8606-02aa6c20b506" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2a7300ab-4653-491e-8606-02aa6c20b506_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_2a7300ab-4653-491e-8606-02aa6c20b506" xlink:to="loc_srt_RangeMember_2a7300ab-4653-491e-8606-02aa6c20b506_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_1264d17b-46e4-404e-84e0-80b08e4ea37a" 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_2a7300ab-4653-491e-8606-02aa6c20b506" xlink:to="loc_srt_RangeMember_1264d17b-46e4-404e-84e0-80b08e4ea37a" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/CommitmentsandContingenciesNarrativeDetails" xlink:type="simple" xlink:href="lii-20240331.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_81eae77a-f718-4022-b153-c0d7604643ff" 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_c902edd8-7130-4a36-bef7-d22bec4ee51b" 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_81eae77a-f718-4022-b153-c0d7604643ff" xlink:to="loc_us-gaap_LossContingenciesTable_c902edd8-7130-4a36-bef7-d22bec4ee51b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_110a32bd-5070-44e3-9c56-b77b5a2e1070" 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_c902edd8-7130-4a36-bef7-d22bec4ee51b" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_110a32bd-5070-44e3-9c56-b77b5a2e1070" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_110a32bd-5070-44e3-9c56-b77b5a2e1070_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_110a32bd-5070-44e3-9c56-b77b5a2e1070" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_110a32bd-5070-44e3-9c56-b77b5a2e1070_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_7d9f54fe-a790-46f0-9f23-3798212b649e" 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_110a32bd-5070-44e3-9c56-b77b5a2e1070" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_7d9f54fe-a790-46f0-9f23-3798212b649e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_63b82038-9a11-4a7e-83ce-8de64f28a4c1" 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_c902edd8-7130-4a36-bef7-d22bec4ee51b" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_63b82038-9a11-4a7e-83ce-8de64f28a4c1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_63b82038-9a11-4a7e-83ce-8de64f28a4c1_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_63b82038-9a11-4a7e-83ce-8de64f28a4c1" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_63b82038-9a11-4a7e-83ce-8de64f28a4c1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_a7cc55e1-f36b-453a-93cf-ff12de4916c1" 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_63b82038-9a11-4a7e-83ce-8de64f28a4c1" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_a7cc55e1-f36b-453a-93cf-ff12de4916c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_2a655e24-f19a-4cfe-b92f-27c8f6737118" 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_c902edd8-7130-4a36-bef7-d22bec4ee51b" xlink:to="loc_srt_LitigationCaseAxis_2a655e24-f19a-4cfe-b92f-27c8f6737118" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_2a655e24-f19a-4cfe-b92f-27c8f6737118_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_2a655e24-f19a-4cfe-b92f-27c8f6737118" xlink:to="loc_srt_LitigationCaseTypeDomain_2a655e24-f19a-4cfe-b92f-27c8f6737118_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_c495a1a7-9433-4ffb-b698-1eb5a73f6842" 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_2a655e24-f19a-4cfe-b92f-27c8f6737118" xlink:to="loc_srt_LitigationCaseTypeDomain_c495a1a7-9433-4ffb-b698-1eb5a73f6842" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusAxis_942e3f81-d4fd-43a4-8a74-33e5be9ef06e" 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_c902edd8-7130-4a36-bef7-d22bec4ee51b" xlink:to="loc_us-gaap_LitigationStatusAxis_942e3f81-d4fd-43a4-8a74-33e5be9ef06e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_942e3f81-d4fd-43a4-8a74-33e5be9ef06e_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_942e3f81-d4fd-43a4-8a74-33e5be9ef06e" xlink:to="loc_us-gaap_LitigationStatusDomain_942e3f81-d4fd-43a4-8a74-33e5be9ef06e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationStatusDomain_a1ff29aa-a578-4843-a712-a58cdda0ff1e" 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_942e3f81-d4fd-43a4-8a74-33e5be9ef06e" xlink:to="loc_us-gaap_LitigationStatusDomain_a1ff29aa-a578-4843-a712-a58cdda0ff1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_3b71a63e-773f-44a5-a9f4-1e447b6ed7f3" 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_c902edd8-7130-4a36-bef7-d22bec4ee51b" xlink:to="loc_us-gaap_LossContingenciesByNatureOfContingencyAxis_3b71a63e-773f-44a5-a9f4-1e447b6ed7f3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_3b71a63e-773f-44a5-a9f4-1e447b6ed7f3_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_3b71a63e-773f-44a5-a9f4-1e447b6ed7f3" xlink:to="loc_us-gaap_LossContingencyNatureDomain_3b71a63e-773f-44a5-a9f4-1e447b6ed7f3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNatureDomain_e4f3d4c6-c1bc-4b7b-8436-0901ffd6b04c" 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_3b71a63e-773f-44a5-a9f4-1e447b6ed7f3" xlink:to="loc_us-gaap_LossContingencyNatureDomain_e4f3d4c6-c1bc-4b7b-8436-0901ffd6b04c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_61e4fbaf-92f0-48b4-ab90-9261b435b584" 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_c902edd8-7130-4a36-bef7-d22bec4ee51b" xlink:to="loc_srt_RangeAxis_61e4fbaf-92f0-48b4-ab90-9261b435b584" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_61e4fbaf-92f0-48b4-ab90-9261b435b584_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_61e4fbaf-92f0-48b4-ab90-9261b435b584" xlink:to="loc_srt_RangeMember_61e4fbaf-92f0-48b4-ab90-9261b435b584_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_bc775184-f9cc-49a6-9fdd-5c1af67659cc" 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_61e4fbaf-92f0-48b4-ab90-9261b435b584" xlink:to="loc_srt_RangeMember_bc775184-f9cc-49a6-9fdd-5c1af67659cc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_OperatingLeaseRightOfUseAssetPercentageRelatedToLeasesOfRealEstate_ba93a438-eed9-4c93-8e98-466e239400ae" xlink:href="lii-20240331.xsd#lii_OperatingLeaseRightOfUseAssetPercentageRelatedToLeasesOfRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_81eae77a-f718-4022-b153-c0d7604643ff" xlink:to="loc_lii_OperatingLeaseRightOfUseAssetPercentageRelatedToLeasesOfRealEstate_ba93a438-eed9-4c93-8e98-466e239400ae" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/RevenueRecognitionNarrativeDetails" xlink:type="simple" xlink:href="lii-20240331.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_65de3efb-a3f8-4926-b092-92f6ce5e7891" 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_d03e90a8-c1b8-4c93-b787-bb7888d910e3" 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_65de3efb-a3f8-4926-b092-92f6ce5e7891" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_d03e90a8-c1b8-4c93-b787-bb7888d910e3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_ddf13860-f59b-4ae2-8b93-277056ed2d16" 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_d03e90a8-c1b8-4c93-b787-bb7888d910e3" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_ddf13860-f59b-4ae2-8b93-277056ed2d16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_ddf13860-f59b-4ae2-8b93-277056ed2d16_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_ddf13860-f59b-4ae2-8b93-277056ed2d16" xlink:to="loc_us-gaap_SegmentDomain_ddf13860-f59b-4ae2-8b93-277056ed2d16_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_de35c029-fdba-4241-a53b-06eb9c7312ab" 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_ddf13860-f59b-4ae2-8b93-277056ed2d16" xlink:to="loc_us-gaap_SegmentDomain_de35c029-fdba-4241-a53b-06eb9c7312ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ResidentialHeatingAndCoolingMember_406574a1-a597-4a32-ad5d-231bd7eb8eb4" xlink:href="lii-20240331.xsd#lii_ResidentialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_de35c029-fdba-4241-a53b-06eb9c7312ab" xlink:to="loc_lii_ResidentialHeatingAndCoolingMember_406574a1-a597-4a32-ad5d-231bd7eb8eb4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_9a593b26-f1f1-4d36-8c89-60e09969721e" xlink:href="lii-20240331.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_de35c029-fdba-4241-a53b-06eb9c7312ab" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_9a593b26-f1f1-4d36-8c89-60e09969721e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_d2726e84-e581-47a2-be60-92b6473bcff3" 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_d03e90a8-c1b8-4c93-b787-bb7888d910e3" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_d2726e84-e581-47a2-be60-92b6473bcff3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_d2726e84-e581-47a2-be60-92b6473bcff3_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_d2726e84-e581-47a2-be60-92b6473bcff3" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_d2726e84-e581-47a2-be60-92b6473bcff3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_c14086f7-7d17-498c-ba24-48f0ac7a8749" 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_d2726e84-e581-47a2-be60-92b6473bcff3" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_c14086f7-7d17-498c-ba24-48f0ac7a8749" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelDirectlyToConsumerMember_7667f7e8-69da-4fef-8c1a-f69ac4ae7250" 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_c14086f7-7d17-498c-ba24-48f0ac7a8749" xlink:to="loc_us-gaap_SalesChannelDirectlyToConsumerMember_7667f7e8-69da-4fef-8c1a-f69ac4ae7250" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_eec1e4dc-c3a1-4da3-b514-f9f523efdae7" 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_d03e90a8-c1b8-4c93-b787-bb7888d910e3" xlink:to="loc_srt_ProductOrServiceAxis_eec1e4dc-c3a1-4da3-b514-f9f523efdae7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_eec1e4dc-c3a1-4da3-b514-f9f523efdae7_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_eec1e4dc-c3a1-4da3-b514-f9f523efdae7" xlink:to="loc_srt_ProductsAndServicesDomain_eec1e4dc-c3a1-4da3-b514-f9f523efdae7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_3fc672ee-eba2-4819-a55a-805999e0f8b2" 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_eec1e4dc-c3a1-4da3-b514-f9f523efdae7" xlink:to="loc_srt_ProductsAndServicesDomain_3fc672ee-eba2-4819-a55a-805999e0f8b2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_EquipmentSalesMember_5fdd71b8-dd57-4444-aa7d-f20fe5e83b6c" xlink:href="lii-20240331.xsd#lii_EquipmentSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_3fc672ee-eba2-4819-a55a-805999e0f8b2" xlink:to="loc_lii_EquipmentSalesMember_5fdd71b8-dd57-4444-aa7d-f20fe5e83b6c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_d5c34579-735f-4c6b-b35f-96c6c67d9ddf" xlink:href="lii-20240331.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_3fc672ee-eba2-4819-a55a-805999e0f8b2" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_d5c34579-735f-4c6b-b35f-96c6c67d9ddf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_266067d5-e6ee-4376-a9ab-42461238cf41" 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_65de3efb-a3f8-4926-b092-92f6ce5e7891" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_266067d5-e6ee-4376-a9ab-42461238cf41" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_26176441-c1fa-4dda-99ac-e25bab489b58" 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_65de3efb-a3f8-4926-b092-92f6ce5e7891" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_26176441-c1fa-4dda-99ac-e25bab489b58" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/RevenueRecognitionRevenuebyBusinessSegmentbyGeographyDetails" xlink:type="simple" xlink:href="lii-20240331.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_378fd8bf-3ad6-4d19-8666-9af6ee571cdd" 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_e8099a10-8a1f-4790-bad8-89750d25bec3" 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_378fd8bf-3ad6-4d19-8666-9af6ee571cdd" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_e8099a10-8a1f-4790-bad8-89750d25bec3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicDistributionAxis_47c992e9-da95-4569-9b7a-a6b89d4e6cba" 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_e8099a10-8a1f-4790-bad8-89750d25bec3" xlink:to="loc_us-gaap_GeographicDistributionAxis_47c992e9-da95-4569-9b7a-a6b89d4e6cba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicDistributionDomain_47c992e9-da95-4569-9b7a-a6b89d4e6cba_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_47c992e9-da95-4569-9b7a-a6b89d4e6cba" xlink:to="loc_us-gaap_GeographicDistributionDomain_47c992e9-da95-4569-9b7a-a6b89d4e6cba_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeographicDistributionDomain_9523e2ea-6572-4fc3-b996-7138ef930caf" 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_47c992e9-da95-4569-9b7a-a6b89d4e6cba" xlink:to="loc_us-gaap_GeographicDistributionDomain_9523e2ea-6572-4fc3-b996-7138ef930caf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_InternationalMember_a1a5195e-c542-4284-bfe1-fec948d459bb" xlink:href="lii-20240331.xsd#lii_InternationalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GeographicDistributionDomain_9523e2ea-6572-4fc3-b996-7138ef930caf" xlink:to="loc_lii_InternationalMember_a1a5195e-c542-4284-bfe1-fec948d459bb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_CA_07224860-13ce-43e5-912d-38be45d66321" 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_9523e2ea-6572-4fc3-b996-7138ef930caf" xlink:to="loc_country_CA_07224860-13ce-43e5-912d-38be45d66321" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_US_c021dfbf-d33b-4051-bf50-1280b5acab6a" 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_9523e2ea-6572-4fc3-b996-7138ef930caf" xlink:to="loc_country_US_c021dfbf-d33b-4051-bf50-1280b5acab6a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_61367d46-c438-4f25-a5ba-0bf5a4778891" 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_e8099a10-8a1f-4790-bad8-89750d25bec3" xlink:to="loc_srt_ProductOrServiceAxis_61367d46-c438-4f25-a5ba-0bf5a4778891" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_61367d46-c438-4f25-a5ba-0bf5a4778891_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_61367d46-c438-4f25-a5ba-0bf5a4778891" xlink:to="loc_srt_ProductsAndServicesDomain_61367d46-c438-4f25-a5ba-0bf5a4778891_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_9775cb4a-b139-4884-a4d9-d550c7e9cab4" 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_61367d46-c438-4f25-a5ba-0bf5a4778891" xlink:to="loc_srt_ProductsAndServicesDomain_9775cb4a-b139-4884-a4d9-d550c7e9cab4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_EquipmentSalesMember_4b07c019-dd0f-4aec-a8f7-b0633a4c8661" xlink:href="lii-20240331.xsd#lii_EquipmentSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_9775cb4a-b139-4884-a4d9-d550c7e9cab4" xlink:to="loc_lii_EquipmentSalesMember_4b07c019-dd0f-4aec-a8f7-b0633a4c8661" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_702b4584-1326-45df-99e8-67f8c03db971" xlink:href="lii-20240331.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_9775cb4a-b139-4884-a4d9-d550c7e9cab4" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_702b4584-1326-45df-99e8-67f8c03db971" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_09334779-341b-4de2-b155-2a9e0afee472" 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_e8099a10-8a1f-4790-bad8-89750d25bec3" xlink:to="loc_srt_StatementGeographicalAxis_09334779-341b-4de2-b155-2a9e0afee472" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_09334779-341b-4de2-b155-2a9e0afee472_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_09334779-341b-4de2-b155-2a9e0afee472" xlink:to="loc_srt_SegmentGeographicalDomain_09334779-341b-4de2-b155-2a9e0afee472_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_d5ff3448-8fad-44cf-9d10-c0f6f03b4116" 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_09334779-341b-4de2-b155-2a9e0afee472" xlink:to="loc_srt_SegmentGeographicalDomain_d5ff3448-8fad-44cf-9d10-c0f6f03b4116" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_fd4e927f-b80e-4e59-9762-18c3866100f5" 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_e8099a10-8a1f-4790-bad8-89750d25bec3" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingAxis_fd4e927f-b80e-4e59-9762-18c3866100f5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_fd4e927f-b80e-4e59-9762-18c3866100f5_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_fd4e927f-b80e-4e59-9762-18c3866100f5" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_fd4e927f-b80e-4e59-9762-18c3866100f5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_832578f1-1524-46c3-a005-4f15caabd6ea" 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_fd4e927f-b80e-4e59-9762-18c3866100f5" xlink:to="loc_us-gaap_ContractWithCustomerBasisOfPricingDomain_832578f1-1524-46c3-a005-4f15caabd6ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelDirectlyToConsumerMember_3803b19b-e63b-46ce-bc73-5869887a0baa" 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_832578f1-1524-46c3-a005-4f15caabd6ea" xlink:to="loc_us-gaap_SalesChannelDirectlyToConsumerMember_3803b19b-e63b-46ce-bc73-5869887a0baa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerDurationAxis_18e66e8a-3d03-46f1-b0a2-20dfba0b2d18" 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_e8099a10-8a1f-4790-bad8-89750d25bec3" xlink:to="loc_us-gaap_ContractWithCustomerDurationAxis_18e66e8a-3d03-46f1-b0a2-20dfba0b2d18" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerDurationDomain_18e66e8a-3d03-46f1-b0a2-20dfba0b2d18_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_18e66e8a-3d03-46f1-b0a2-20dfba0b2d18" xlink:to="loc_us-gaap_ContractWithCustomerDurationDomain_18e66e8a-3d03-46f1-b0a2-20dfba0b2d18_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerDurationDomain_c5d4bd4d-e773-43d0-82e6-b4efcbfc4203" 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_18e66e8a-3d03-46f1-b0a2-20dfba0b2d18" xlink:to="loc_us-gaap_ContractWithCustomerDurationDomain_c5d4bd4d-e773-43d0-82e6-b4efcbfc4203" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_f3a0617b-7b5f-4e02-ad5d-d7c74c076f66" 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_e8099a10-8a1f-4790-bad8-89750d25bec3" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_f3a0617b-7b5f-4e02-ad5d-d7c74c076f66" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_f3a0617b-7b5f-4e02-ad5d-d7c74c076f66_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_f3a0617b-7b5f-4e02-ad5d-d7c74c076f66" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_f3a0617b-7b5f-4e02-ad5d-d7c74c076f66_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_5a088eed-3020-4804-ab81-74fa75c753f8" 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_f3a0617b-7b5f-4e02-ad5d-d7c74c076f66" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_5a088eed-3020-4804-ab81-74fa75c753f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelAxis_8346e681-4b35-4310-aa68-7166891d9b02" 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_e8099a10-8a1f-4790-bad8-89750d25bec3" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelAxis_8346e681-4b35-4310-aa68-7166891d9b02" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_8346e681-4b35-4310-aa68-7166891d9b02_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_8346e681-4b35-4310-aa68-7166891d9b02" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_8346e681-4b35-4310-aa68-7166891d9b02_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerSalesChannelDomain_3b8657d8-d57a-45e9-bcd1-04647f424a60" 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_8346e681-4b35-4310-aa68-7166891d9b02" xlink:to="loc_us-gaap_ContractWithCustomerSalesChannelDomain_3b8657d8-d57a-45e9-bcd1-04647f424a60" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesChannelDirectlyToConsumerMember_7779d6f8-5b0c-4671-8d86-f3426b430937" 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_3b8657d8-d57a-45e9-bcd1-04647f424a60" xlink:to="loc_us-gaap_SalesChannelDirectlyToConsumerMember_7779d6f8-5b0c-4671-8d86-f3426b430937" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_b76beac7-43ea-4c8e-b5d2-8b918c309b70" 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_e8099a10-8a1f-4790-bad8-89750d25bec3" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_b76beac7-43ea-4c8e-b5d2-8b918c309b70" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_b76beac7-43ea-4c8e-b5d2-8b918c309b70_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_b76beac7-43ea-4c8e-b5d2-8b918c309b70" xlink:to="loc_us-gaap_SegmentDomain_b76beac7-43ea-4c8e-b5d2-8b918c309b70_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_1d0b4460-6a60-4ac8-b5ed-1f9e0f56f297" 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_b76beac7-43ea-4c8e-b5d2-8b918c309b70" xlink:to="loc_us-gaap_SegmentDomain_1d0b4460-6a60-4ac8-b5ed-1f9e0f56f297" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ResidentialHeatingAndCoolingMember_f11abd14-1ed2-403a-84ec-0d144dbf9809" xlink:href="lii-20240331.xsd#lii_ResidentialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_1d0b4460-6a60-4ac8-b5ed-1f9e0f56f297" xlink:to="loc_lii_ResidentialHeatingAndCoolingMember_f11abd14-1ed2-403a-84ec-0d144dbf9809" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_5df80720-d1a8-4995-9bec-c244aa619bd2" xlink:href="lii-20240331.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_1d0b4460-6a60-4ac8-b5ed-1f9e0f56f297" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_5df80720-d1a8-4995-9bec-c244aa619bd2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateAndOtherMember_d95ccbeb-ec14-4b21-8e8a-89a9e52a7ace" 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_1d0b4460-6a60-4ac8-b5ed-1f9e0f56f297" xlink:to="loc_us-gaap_CorporateAndOtherMember_d95ccbeb-ec14-4b21-8e8a-89a9e52a7ace" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_030f6697-f78a-4626-8905-7c0012463500" 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_e8099a10-8a1f-4790-bad8-89750d25bec3" xlink:to="loc_srt_MajorCustomersAxis_030f6697-f78a-4626-8905-7c0012463500" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_030f6697-f78a-4626-8905-7c0012463500_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_030f6697-f78a-4626-8905-7c0012463500" xlink:to="loc_srt_NameOfMajorCustomerDomain_030f6697-f78a-4626-8905-7c0012463500_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_0ce13366-0ac7-4de8-878e-65570a2d9b70" 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_030f6697-f78a-4626-8905-7c0012463500" xlink:to="loc_srt_NameOfMajorCustomerDomain_0ce13366-0ac7-4de8-878e-65570a2d9b70" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_26bc020e-b2a3-47f4-a20a-370c613f53a5" 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_378fd8bf-3ad6-4d19-8666-9af6ee571cdd" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_26bc020e-b2a3-47f4-a20a-370c613f53a5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_9035701b-42e8-4f0d-854a-d9afa5f03dc5" 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_378fd8bf-3ad6-4d19-8666-9af6ee571cdd" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_9035701b-42e8-4f0d-854a-d9afa5f03dc5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_0d8bfc7c-54b6-4b58-b037-a2537c9f2ead" 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_378fd8bf-3ad6-4d19-8666-9af6ee571cdd" xlink:to="loc_us-gaap_Revenues_0d8bfc7c-54b6-4b58-b037-a2537c9f2ead" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/GoodwillDetails" xlink:type="simple" xlink:href="lii-20240331.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_8954368a-0635-4093-a367-9255a0fd5fd3" 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_f8f3e9bc-8034-40b4-a4ed-f36bd1368637" 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_8954368a-0635-4093-a367-9255a0fd5fd3" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_f8f3e9bc-8034-40b4-a4ed-f36bd1368637" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_b4be79ce-0299-4d9b-abe1-f9739bf0c761" 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_f8f3e9bc-8034-40b4-a4ed-f36bd1368637" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_b4be79ce-0299-4d9b-abe1-f9739bf0c761" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_b4be79ce-0299-4d9b-abe1-f9739bf0c761_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_b4be79ce-0299-4d9b-abe1-f9739bf0c761" xlink:to="loc_us-gaap_SegmentDomain_b4be79ce-0299-4d9b-abe1-f9739bf0c761_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_a8010256-c656-41df-b096-bbf1fd94c25c" 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_b4be79ce-0299-4d9b-abe1-f9739bf0c761" xlink:to="loc_us-gaap_SegmentDomain_a8010256-c656-41df-b096-bbf1fd94c25c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ResidentialHeatingAndCoolingMember_3a0823df-971e-42d7-9815-2ab65b16848a" xlink:href="lii-20240331.xsd#lii_ResidentialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_a8010256-c656-41df-b096-bbf1fd94c25c" xlink:to="loc_lii_ResidentialHeatingAndCoolingMember_3a0823df-971e-42d7-9815-2ab65b16848a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialHeatingAndCoolingMember_8dbd1e56-45d3-4836-b5ed-ea998ce9ea04" xlink:href="lii-20240331.xsd#lii_CommercialHeatingAndCoolingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_a8010256-c656-41df-b096-bbf1fd94c25c" xlink:to="loc_lii_CommercialHeatingAndCoolingMember_8dbd1e56-45d3-4836-b5ed-ea998ce9ea04" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_a6f36aa9-e198-4e40-b534-913fc6fb35b1" 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_f8f3e9bc-8034-40b4-a4ed-f36bd1368637" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_a6f36aa9-e198-4e40-b534-913fc6fb35b1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_a6f36aa9-e198-4e40-b534-913fc6fb35b1_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_a6f36aa9-e198-4e40-b534-913fc6fb35b1" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_a6f36aa9-e198-4e40-b534-913fc6fb35b1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ed74143-4d5e-4882-a82d-22e0b94914d4" 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_a6f36aa9-e198-4e40-b534-913fc6fb35b1" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ed74143-4d5e-4882-a82d-22e0b94914d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_AESMember_00191a8c-7a76-41fd-9618-b7e0dacc5a9b" xlink:href="lii-20240331.xsd#lii_AESMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_0ed74143-4d5e-4882-a82d-22e0b94914d4" xlink:to="loc_lii_AESMember_00191a8c-7a76-41fd-9618-b7e0dacc5a9b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillRollForward_afd69efc-20c0-4aef-bf89-5b9fef5aacb7" 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_8954368a-0635-4093-a367-9255a0fd5fd3" xlink:to="loc_us-gaap_GoodwillRollForward_afd69efc-20c0-4aef-bf89-5b9fef5aacb7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_2af0a89d-47f8-495e-9e59-023d3c741b2a" 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_afd69efc-20c0-4aef-bf89-5b9fef5aacb7" xlink:to="loc_us-gaap_Goodwill_2af0a89d-47f8-495e-9e59-023d3c741b2a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_fe30d253-b71d-4834-8e7a-bea92b4ab9d9" 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_afd69efc-20c0-4aef-bf89-5b9fef5aacb7" xlink:to="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_fe30d253-b71d-4834-8e7a-bea92b4ab9d9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_8519c15d-4bf5-4e71-9028-52974db10ba8" 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-20240331.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_affa9a6b-87b7-431a-9bef-7e59196581f1" 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_8b3eacc4-8ae4-4236-a6d7-707155906d2d" 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_affa9a6b-87b7-431a-9bef-7e59196581f1" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_8b3eacc4-8ae4-4236-a6d7-707155906d2d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_8b27f2d0-3edf-4f33-bac2-2996be07a7d5" 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_8b3eacc4-8ae4-4236-a6d7-707155906d2d" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_8b27f2d0-3edf-4f33-bac2-2996be07a7d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_8b27f2d0-3edf-4f33-bac2-2996be07a7d5_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_8b27f2d0-3edf-4f33-bac2-2996be07a7d5" xlink:to="loc_us-gaap_HedgingRelationshipDomain_8b27f2d0-3edf-4f33-bac2-2996be07a7d5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_07af5554-7e5f-4989-810c-fe00b0970014" 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_8b27f2d0-3edf-4f33-bac2-2996be07a7d5" xlink:to="loc_us-gaap_HedgingRelationshipDomain_07af5554-7e5f-4989-810c-fe00b0970014" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgingMember_ba92400c-f92f-49c7-945c-6e1c638395b8" 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_07af5554-7e5f-4989-810c-fe00b0970014" xlink:to="loc_us-gaap_CashFlowHedgingMember_ba92400c-f92f-49c7-945c-6e1c638395b8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1_88e32e02-2661-4667-bd15-a106875d4b33" 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_affa9a6b-87b7-431a-9bef-7e59196581f1" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1_88e32e02-2661-4667-bd15-a106875d4b33" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesProvisionBenefitForTax_dfb4fc87-3ac3-4b06-837c-cb2959f9956a" xlink:href="lii-20240331.xsd#lii_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesProvisionBenefitForTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossLineItems_affa9a6b-87b7-431a-9bef-7e59196581f1" xlink:to="loc_lii_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesProvisionBenefitForTax_dfb4fc87-3ac3-4b06-837c-cb2959f9956a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax_b57c5c0d-a7e6-40bb-a3b0-41b75a3babe3" 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_affa9a6b-87b7-431a-9bef-7e59196581f1" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax_b57c5c0d-a7e6-40bb-a3b0-41b75a3babe3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_2141a644-3432-4a6c-b020-a736459a82ae" 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_affa9a6b-87b7-431a-9bef-7e59196581f1" xlink:to="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_2141a644-3432-4a6c-b020-a736459a82ae" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/StockBasedCompensationScheduleofEquityAwardsGrantedinPeriodDetails" xlink:type="simple" xlink:href="lii-20240331.xsd#StockBasedCompensationScheduleofEquityAwardsGrantedinPeriodDetails"/>
  <link:definitionLink xlink:role="http://www.lennoxinternational.com/role/StockBasedCompensationScheduleofEquityAwardsGrantedinPeriodDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1e663036-e547-46d5-a63c-e6d422a25508" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5a79abde-89fa-4468-8d29-3da64553ba66" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1e663036-e547-46d5-a63c-e6d422a25508" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5a79abde-89fa-4468-8d29-3da64553ba66" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_c4caeb58-f292-472d-a46b-5c034fbb3a40" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5a79abde-89fa-4468-8d29-3da64553ba66" xlink:to="loc_us-gaap_AwardTypeAxis_c4caeb58-f292-472d-a46b-5c034fbb3a40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c4caeb58-f292-472d-a46b-5c034fbb3a40_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_c4caeb58-f292-472d-a46b-5c034fbb3a40" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c4caeb58-f292-472d-a46b-5c034fbb3a40_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_e501564d-a47b-4efa-9101-ef33df5db8de" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_c4caeb58-f292-472d-a46b-5c034fbb3a40" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_e501564d-a47b-4efa-9101-ef33df5db8de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_6255aca9-17d5-44db-885c-78c4aa6c18fb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_e501564d-a47b-4efa-9101-ef33df5db8de" xlink:to="loc_us-gaap_PerformanceSharesMember_6255aca9-17d5-44db-885c-78c4aa6c18fb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_a173c5fc-c62d-4346-9846-a497700a4f74" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_e501564d-a47b-4efa-9101-ef33df5db8de" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_a173c5fc-c62d-4346-9846-a497700a4f74" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockAppreciationRightsSARSMember_a6ea24a1-e71a-4ddd-8b07-fd0c2da2e5bf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockAppreciationRightsSARSMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_e501564d-a47b-4efa-9101-ef33df5db8de" xlink:to="loc_us-gaap_StockAppreciationRightsSARSMember_a6ea24a1-e71a-4ddd-8b07-fd0c2da2e5bf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_3d0ebc37-c7c0-431a-a0c6-8981b8674260" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1e663036-e547-46d5-a63c-e6d422a25508" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_3d0ebc37-c7c0-431a-a0c6-8981b8674260" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_c371cd4c-25be-4a26-aa1a-213a1f955372" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_1e663036-e547-46d5-a63c-e6d422a25508" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_c371cd4c-25be-4a26-aa1a-213a1f955372" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsOutstandingDebtObligationsDetails" xlink:type="simple" xlink:href="lii-20240331.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_c9b3abdb-776b-496e-ac30-6ac9235f39f1" 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_82010216-48ad-4ffc-bb53-2d14a7123054" 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_c9b3abdb-776b-496e-ac30-6ac9235f39f1" xlink:to="loc_us-gaap_DebtInstrumentTable_82010216-48ad-4ffc-bb53-2d14a7123054" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_61cecf68-1be7-4048-a931-69454dcf354c" 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_82010216-48ad-4ffc-bb53-2d14a7123054" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_61cecf68-1be7-4048-a931-69454dcf354c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_61cecf68-1be7-4048-a931-69454dcf354c_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_61cecf68-1be7-4048-a931-69454dcf354c" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_61cecf68-1be7-4048-a931-69454dcf354c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_9401e65b-b3d6-47b2-a5db-15ffe57164b5" 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_61cecf68-1be7-4048-a931-69454dcf354c" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_9401e65b-b3d6-47b2-a5db-15ffe57164b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignLineOfCreditMember_a6ff6cdf-b60a-4050-866b-c504408bf3ce" 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_9401e65b-b3d6-47b2-a5db-15ffe57164b5" xlink:to="loc_us-gaap_ForeignLineOfCreditMember_a6ff6cdf-b60a-4050-866b-c504408bf3ce" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_ecc63d80-7cfe-4ca6-8d8b-a05647da1edb" 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_82010216-48ad-4ffc-bb53-2d14a7123054" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_ecc63d80-7cfe-4ca6-8d8b-a05647da1edb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_ecc63d80-7cfe-4ca6-8d8b-a05647da1edb_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_ecc63d80-7cfe-4ca6-8d8b-a05647da1edb" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_ecc63d80-7cfe-4ca6-8d8b-a05647da1edb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_c721e512-6025-4ad2-a813-e82143362caa" 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_ecc63d80-7cfe-4ca6-8d8b-a05647da1edb" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_c721e512-6025-4ad2-a813-e82143362caa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_976ebb28-34e8-438e-9eab-f26e061a062e" 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_c721e512-6025-4ad2-a813-e82143362caa" xlink:to="loc_us-gaap_SeniorNotesMember_976ebb28-34e8-438e-9eab-f26e061a062e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticLineOfCreditMember_7ec86644-a277-4c1e-aa97-45bb661b3adc" 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_c721e512-6025-4ad2-a813-e82143362caa" xlink:to="loc_us-gaap_DomesticLineOfCreditMember_7ec86644-a277-4c1e-aa97-45bb661b3adc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaper_6defb5ec-a3d2-4231-8468-ef14782620f2" 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_c9b3abdb-776b-496e-ac30-6ac9235f39f1" xlink:to="loc_us-gaap_CommercialPaper_6defb5ec-a3d2-4231-8468-ef14782620f2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrentAbstract_8d8c09fb-481b-499e-ac83-8b7dfa12b575" 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_c9b3abdb-776b-496e-ac30-6ac9235f39f1" xlink:to="loc_us-gaap_LongTermDebtCurrentAbstract_8d8c09fb-481b-499e-ac83-8b7dfa12b575" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityCurrent_9e42c8f4-4f6b-4a6c-af60-a2c6ad5b1cd2" 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_8d8c09fb-481b-499e-ac83-8b7dfa12b575" xlink:to="loc_us-gaap_FinanceLeaseLiabilityCurrent_9e42c8f4-4f6b-4a6c-af60-a2c6ad5b1cd2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_bd3bef84-b4f8-4019-8901-8964468739a9" 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_8d8c09fb-481b-499e-ac83-8b7dfa12b575" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent_bd3bef84-b4f8-4019-8901-8964468739a9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract_5d9372cb-4a3c-4333-90ac-f3b9ffb8cf44" 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_c9b3abdb-776b-496e-ac30-6ac9235f39f1" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsAbstract_5d9372cb-4a3c-4333-90ac-f3b9ffb8cf44" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_ca75379f-368e-4599-a319-ca25d58330e4" 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_5d9372cb-4a3c-4333-90ac-f3b9ffb8cf44" xlink:to="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_ca75379f-368e-4599-a319-ca25d58330e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_7dcf35e8-0535-4886-b715-937313ce3b1f" 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_5d9372cb-4a3c-4333-90ac-f3b9ffb8cf44" xlink:to="loc_us-gaap_LongTermDebt_7dcf35e8-0535-4886-b715-937313ce3b1f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNoncurrentGross_772e3a0e-48d1-4ddb-b4ad-f51b6ba2e2f8" 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_5d9372cb-4a3c-4333-90ac-f3b9ffb8cf44" xlink:to="loc_us-gaap_DeferredFinanceCostsNoncurrentGross_772e3a0e-48d1-4ddb-b4ad-f51b6ba2e2f8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_24d13f78-f72b-47c1-ac2c-3071f2d0c254" 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_5d9372cb-4a3c-4333-90ac-f3b9ffb8cf44" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligations_24d13f78-f72b-47c1-ac2c-3071f2d0c254" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtAndCapitalLeaseObligations_fbc1e31d-b29a-4882-9938-b3ab18b3220b" 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_c9b3abdb-776b-496e-ac30-6ac9235f39f1" xlink:to="loc_us-gaap_DebtAndCapitalLeaseObligations_fbc1e31d-b29a-4882-9938-b3ab18b3220b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_b07abed7-cfb2-4ee2-9a33-6bf754b356ba" 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_c9b3abdb-776b-496e-ac30-6ac9235f39f1" xlink:to="loc_us-gaap_ShortTermBorrowings_b07abed7-cfb2-4ee2-9a33-6bf754b356ba" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_cbb226b3-7fd3-4390-a9c1-5c386c4f6ecc" 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_c9b3abdb-776b-496e-ac30-6ac9235f39f1" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_cbb226b3-7fd3-4390-a9c1-5c386c4f6ecc" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsForeignObligationsDetails" xlink:type="simple" xlink:href="lii-20240331.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_99f49412-a2aa-4730-8d0a-f4f8d4f9f1c3" 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_01b4ce35-3c64-4725-a064-225c4329099d" 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_99f49412-a2aa-4730-8d0a-f4f8d4f9f1c3" xlink:to="loc_us-gaap_ScheduleOfShortTermDebtTable_01b4ce35-3c64-4725-a064-225c4329099d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_f50d487b-6863-4d19-b21c-34a191f16029" 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_01b4ce35-3c64-4725-a064-225c4329099d" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_f50d487b-6863-4d19-b21c-34a191f16029" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_f50d487b-6863-4d19-b21c-34a191f16029_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_f50d487b-6863-4d19-b21c-34a191f16029" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_f50d487b-6863-4d19-b21c-34a191f16029_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_ffc42ba8-a3ce-4106-b4f4-85e695627eda" 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_f50d487b-6863-4d19-b21c-34a191f16029" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_ffc42ba8-a3ce-4106-b4f4-85e695627eda" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignLineOfCreditMember_e48dd840-ecec-4d64-bce2-3822cf647e65" 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_ffc42ba8-a3ce-4106-b4f4-85e695627eda" xlink:to="loc_us-gaap_ForeignLineOfCreditMember_e48dd840-ecec-4d64-bce2-3822cf647e65" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_20112d0c-bc07-4866-97e3-0b97c9fb277e" 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_99f49412-a2aa-4730-8d0a-f4f8d4f9f1c3" xlink:to="loc_us-gaap_ShortTermBorrowings_20112d0c-bc07-4866-97e3-0b97c9fb277e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromShortTermDebt_010aef55-c6b8-4823-8247-80999f12a726" 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_99f49412-a2aa-4730-8d0a-f4f8d4f9f1c3" xlink:to="loc_us-gaap_ProceedsFromShortTermDebt_010aef55-c6b8-4823-8247-80999f12a726" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsCommercialPaperProgramDetails" xlink:type="simple" xlink:href="lii-20240331.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_58ff1914-9945-49e3-9112-f26462653292" 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_ded2ce99-f3bf-4e84-aa2e-1705f3856948" 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_58ff1914-9945-49e3-9112-f26462653292" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_ded2ce99-f3bf-4e84-aa2e-1705f3856948" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_0f0a1fb2-57d0-4022-bbf2-45761f2a8a18" 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_ded2ce99-f3bf-4e84-aa2e-1705f3856948" xlink:to="loc_us-gaap_DebtInstrumentAxis_0f0a1fb2-57d0-4022-bbf2-45761f2a8a18" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0f0a1fb2-57d0-4022-bbf2-45761f2a8a18_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_0f0a1fb2-57d0-4022-bbf2-45761f2a8a18" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0f0a1fb2-57d0-4022-bbf2-45761f2a8a18_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_5b193664-019b-4021-855f-8c257ddc5375" 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_0f0a1fb2-57d0-4022-bbf2-45761f2a8a18" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_5b193664-019b-4021-855f-8c257ddc5375" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_741a95e3-5054-4832-a701-b12d1ab13916" 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_5b193664-019b-4021-855f-8c257ddc5375" xlink:to="loc_us-gaap_CommercialPaperMember_741a95e3-5054-4832-a701-b12d1ab13916" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_CommercialPaperMaximumBorrowingCapacity_b8c19b44-c2ed-4391-bf5c-26c93cc95fc2" xlink:href="lii-20240331.xsd#lii_CommercialPaperMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_58ff1914-9945-49e3-9112-f26462653292" xlink:to="loc_lii_CommercialPaperMaximumBorrowingCapacity_b8c19b44-c2ed-4391-bf5c-26c93cc95fc2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_fdf4be89-146d-44d1-8be6-0d255f1d3005" 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_58ff1914-9945-49e3-9112-f26462653292" xlink:to="loc_us-gaap_DebtInstrumentTerm_fdf4be89-146d-44d1-8be6-0d255f1d3005" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaper_be73a557-120e-4f34-8a51-6c05a6d733d2" 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_58ff1914-9945-49e3-9112-f26462653292" xlink:to="loc_us-gaap_CommercialPaper_be73a557-120e-4f34-8a51-6c05a6d733d2" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsDomesticCreditFacilityDetails" xlink:type="simple" xlink:href="lii-20240331.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_1c5b380d-15af-434c-bdad-3cb18ed57ae4" 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_d983d1d5-2658-4686-add3-d0ada3cf61be" 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_1c5b380d-15af-434c-bdad-3cb18ed57ae4" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_d983d1d5-2658-4686-add3-d0ada3cf61be" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_b401c524-1a93-408b-9fb1-78c6ca11a107" 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_d983d1d5-2658-4686-add3-d0ada3cf61be" xlink:to="loc_us-gaap_DebtInstrumentAxis_b401c524-1a93-408b-9fb1-78c6ca11a107" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_b401c524-1a93-408b-9fb1-78c6ca11a107_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_b401c524-1a93-408b-9fb1-78c6ca11a107" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_b401c524-1a93-408b-9fb1-78c6ca11a107_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_cefa8fa2-97cf-43d9-97e4-6b16df5708ce" 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_b401c524-1a93-408b-9fb1-78c6ca11a107" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_cefa8fa2-97cf-43d9-97e4-6b16df5708ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_99075afd-9e4a-44b1-95bf-b4b9c2b365ae" 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_cefa8fa2-97cf-43d9-97e4-6b16df5708ce" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_99075afd-9e4a-44b1-95bf-b4b9c2b365ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2025NotesMember_4109e27a-adb4-41d9-99b4-14a1248fc6a2" xlink:href="lii-20240331.xsd#lii_A2025NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_cefa8fa2-97cf-43d9-97e4-6b16df5708ce" xlink:to="loc_lii_A2025NotesMember_4109e27a-adb4-41d9-99b4-14a1248fc6a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2027NotesMember_7b11c6f9-62b1-484c-bd8a-2cae8e5a1f92" xlink:href="lii-20240331.xsd#lii_A2027NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_cefa8fa2-97cf-43d9-97e4-6b16df5708ce" xlink:to="loc_lii_A2027NotesMember_7b11c6f9-62b1-484c-bd8a-2cae8e5a1f92" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_38509e15-09e6-4fec-aba6-5c33badb4d78" 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_d983d1d5-2658-4686-add3-d0ada3cf61be" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_38509e15-09e6-4fec-aba6-5c33badb4d78" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_38509e15-09e6-4fec-aba6-5c33badb4d78_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_38509e15-09e6-4fec-aba6-5c33badb4d78" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_38509e15-09e6-4fec-aba6-5c33badb4d78_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_9ad0fe16-22c1-4200-b23c-d9c66ec2e61e" 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_38509e15-09e6-4fec-aba6-5c33badb4d78" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_9ad0fe16-22c1-4200-b23c-d9c66ec2e61e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MediumTermNotesMember_48ee01a0-1b22-4b61-94a5-45c6b2e3868b" 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_9ad0fe16-22c1-4200-b23c-d9c66ec2e61e" xlink:to="loc_us-gaap_MediumTermNotesMember_48ee01a0-1b22-4b61-94a5-45c6b2e3868b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_7e6d2254-68b6-4ecd-9da3-87c9e6dc550d" 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_9ad0fe16-22c1-4200-b23c-d9c66ec2e61e" xlink:to="loc_us-gaap_SeniorNotesMember_7e6d2254-68b6-4ecd-9da3-87c9e6dc550d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_fe63bce1-6920-4218-95e5-f016595b87fc" 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_d983d1d5-2658-4686-add3-d0ada3cf61be" xlink:to="loc_us-gaap_CreditFacilityAxis_fe63bce1-6920-4218-95e5-f016595b87fc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_fe63bce1-6920-4218-95e5-f016595b87fc_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_fe63bce1-6920-4218-95e5-f016595b87fc" xlink:to="loc_us-gaap_CreditFacilityDomain_fe63bce1-6920-4218-95e5-f016595b87fc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_320a010f-9698-44bd-9d5e-af3013b31ec2" 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_fe63bce1-6920-4218-95e5-f016595b87fc" xlink:to="loc_us-gaap_CreditFacilityDomain_320a010f-9698-44bd-9d5e-af3013b31ec2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DomesticCreditFacilityMember_301d5af7-3f6c-4988-a8c7-527f654fee66" xlink:href="lii-20240331.xsd#lii_DomesticCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_320a010f-9698-44bd-9d5e-af3013b31ec2" xlink:to="loc_lii_DomesticCreditFacilityMember_301d5af7-3f6c-4988-a8c7-527f654fee66" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_07e17583-c3aa-4053-b9aa-06227569534a" 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_320a010f-9698-44bd-9d5e-af3013b31ec2" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_07e17583-c3aa-4053-b9aa-06227569534a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_SubfacilityforSwinglineLoansMember_20b1f83e-2519-423d-b51f-7e45baf71426" xlink:href="lii-20240331.xsd#lii_SubfacilityforSwinglineLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_320a010f-9698-44bd-9d5e-af3013b31ec2" xlink:to="loc_lii_SubfacilityforSwinglineLoansMember_20b1f83e-2519-423d-b51f-7e45baf71426" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_775ee942-cd73-48b9-9e00-efb1075b434c" 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_1c5b380d-15af-434c-bdad-3cb18ed57ae4" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_775ee942-cd73-48b9-9e00-efb1075b434c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_10b1f5f2-f7a5-404c-96db-4905d2e25d1d" 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_1c5b380d-15af-434c-bdad-3cb18ed57ae4" xlink:to="loc_us-gaap_LineOfCredit_10b1f5f2-f7a5-404c-96db-4905d2e25d1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_RevolvingCreditFacilityCommittedToStandByLettersOfCredit_f77343f3-0a2e-4ead-924a-b813d9f650da" xlink:href="lii-20240331.xsd#lii_RevolvingCreditFacilityCommittedToStandByLettersOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_1c5b380d-15af-434c-bdad-3cb18ed57ae4" xlink:to="loc_lii_RevolvingCreditFacilityCommittedToStandByLettersOfCredit_f77343f3-0a2e-4ead-924a-b813d9f650da" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_21c02ce0-1910-4fbf-bf7f-10399d9c458d" 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_1c5b380d-15af-434c-bdad-3cb18ed57ae4" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_21c02ce0-1910-4fbf-bf7f-10399d9c458d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_515fbce7-8b0e-4245-a141-a3ae61fe1fd9" 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_1c5b380d-15af-434c-bdad-3cb18ed57ae4" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_515fbce7-8b0e-4245-a141-a3ae61fe1fd9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentNumberOfExtensionOptions_357fcda4-eb45-4d3d-b787-3a0cba6157bf" xlink:href="lii-20240331.xsd#lii_DebtInstrumentNumberOfExtensionOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_1c5b380d-15af-434c-bdad-3cb18ed57ae4" xlink:to="loc_lii_DebtInstrumentNumberOfExtensionOptions_357fcda4-eb45-4d3d-b787-3a0cba6157bf" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentTermOfExtensionOptions_c00f6a92-5a98-4d62-8722-04d9e6775542" xlink:href="lii-20240331.xsd#lii_DebtInstrumentTermOfExtensionOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_1c5b380d-15af-434c-bdad-3cb18ed57ae4" xlink:to="loc_lii_DebtInstrumentTermOfExtensionOptions_c00f6a92-5a98-4d62-8722-04d9e6775542" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentCovenantNetLeverageRatio_1068280f-d83f-4759-814e-f2279f7ba97e" xlink:href="lii-20240331.xsd#lii_DebtInstrumentCovenantNetLeverageRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_1c5b380d-15af-434c-bdad-3cb18ed57ae4" xlink:to="loc_lii_DebtInstrumentCovenantNetLeverageRatio_1068280f-d83f-4759-814e-f2279f7ba97e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentCovenantNetLeverageRatioFollowingMaterialAcquisition_5fc87f46-d35b-4860-8740-f8318cdbbd11" xlink:href="lii-20240331.xsd#lii_DebtInstrumentCovenantNetLeverageRatioFollowingMaterialAcquisition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_1c5b380d-15af-434c-bdad-3cb18ed57ae4" xlink:to="loc_lii_DebtInstrumentCovenantNetLeverageRatioFollowingMaterialAcquisition_5fc87f46-d35b-4860-8740-f8318cdbbd11" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization_45ecde89-1173-448e-89d6-3b60b0f168e8" xlink:href="lii-20240331.xsd#lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_1c5b380d-15af-434c-bdad-3cb18ed57ae4" xlink:to="loc_lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization_45ecde89-1173-448e-89d6-3b60b0f168e8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentSeriesOfDebtNotes_4e633087-deb2-46b5-9b24-aebe7a61bd75" xlink:href="lii-20240331.xsd#lii_DebtInstrumentSeriesOfDebtNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_1c5b380d-15af-434c-bdad-3cb18ed57ae4" xlink:to="loc_lii_DebtInstrumentSeriesOfDebtNotes_4e633087-deb2-46b5-9b24-aebe7a61bd75" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_ba974fd1-3841-4836-b3c4-a01edc8e634b" 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_1c5b380d-15af-434c-bdad-3cb18ed57ae4" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_ba974fd1-3841-4836-b3c4-a01edc8e634b" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsWeightedAverageBorrowingRateDetails" xlink:type="simple" xlink:href="lii-20240331.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_3ba1d803-2ccd-4ce7-aa03-3a29e5d1c052" 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_39bd5e63-9e4f-4c64-ba36-33e3ba7cde66" 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_3ba1d803-2ccd-4ce7-aa03-3a29e5d1c052" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_39bd5e63-9e4f-4c64-ba36-33e3ba7cde66" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_89a7221e-e7fa-461f-b146-8bbb5baf4d1a" 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_39bd5e63-9e4f-4c64-ba36-33e3ba7cde66" xlink:to="loc_us-gaap_DebtInstrumentAxis_89a7221e-e7fa-461f-b146-8bbb5baf4d1a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_89a7221e-e7fa-461f-b146-8bbb5baf4d1a_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_89a7221e-e7fa-461f-b146-8bbb5baf4d1a" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_89a7221e-e7fa-461f-b146-8bbb5baf4d1a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_731a2aa6-7ad3-4a03-a34d-0fc22d57912c" 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_89a7221e-e7fa-461f-b146-8bbb5baf4d1a" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_731a2aa6-7ad3-4a03-a34d-0fc22d57912c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_87dd5a1b-6381-4f8c-aa01-935a874962e6" 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_731a2aa6-7ad3-4a03-a34d-0fc22d57912c" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_87dd5a1b-6381-4f8c-aa01-935a874962e6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_dbec273b-f730-439a-a2ec-9e973daf7c0d" 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_731a2aa6-7ad3-4a03-a34d-0fc22d57912c" xlink:to="loc_us-gaap_CommercialPaperMember_dbec273b-f730-439a-a2ec-9e973daf7c0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_a6e3b10b-fd16-4f61-828e-a122d4cea9ee" 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_3ba1d803-2ccd-4ce7-aa03-3a29e5d1c052" xlink:to="loc_us-gaap_LongtermDebtWeightedAverageInterestRate_a6e3b10b-fd16-4f61-828e-a122d4cea9ee" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/LinesofCreditandFinancingArrangementsSeniorUnsecuredNotesDetails" xlink:type="simple" xlink:href="lii-20240331.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_d6f5f927-07bf-4abc-8dfd-000fcdd40340" 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_79ad1022-521d-4fde-b079-9f2d459c58eb" 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_d6f5f927-07bf-4abc-8dfd-000fcdd40340" xlink:to="loc_us-gaap_DebtInstrumentTable_79ad1022-521d-4fde-b079-9f2d459c58eb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_4e0483e8-7598-4763-83ed-0ff9c8a67bec" 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_79ad1022-521d-4fde-b079-9f2d459c58eb" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_4e0483e8-7598-4763-83ed-0ff9c8a67bec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_4e0483e8-7598-4763-83ed-0ff9c8a67bec_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_4e0483e8-7598-4763-83ed-0ff9c8a67bec" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_4e0483e8-7598-4763-83ed-0ff9c8a67bec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_535a1c82-73a0-4aac-af0d-4b309db28535" 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_4e0483e8-7598-4763-83ed-0ff9c8a67bec" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_535a1c82-73a0-4aac-af0d-4b309db28535" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_ebb30fa0-3628-4ec3-b297-f9dacdd63f28" 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_535a1c82-73a0-4aac-af0d-4b309db28535" xlink:to="loc_us-gaap_SeniorNotesMember_ebb30fa0-3628-4ec3-b297-f9dacdd63f28" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_fe171e7b-cb9f-4dbc-8173-a87ac9b885b1" 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_79ad1022-521d-4fde-b079-9f2d459c58eb" xlink:to="loc_us-gaap_DebtInstrumentAxis_fe171e7b-cb9f-4dbc-8173-a87ac9b885b1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_fe171e7b-cb9f-4dbc-8173-a87ac9b885b1_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_fe171e7b-cb9f-4dbc-8173-a87ac9b885b1" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_fe171e7b-cb9f-4dbc-8173-a87ac9b885b1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_62ac63e9-3d58-46dc-ae8b-88e13cf92a50" 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_fe171e7b-cb9f-4dbc-8173-a87ac9b885b1" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_62ac63e9-3d58-46dc-ae8b-88e13cf92a50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2025NotesMember_290a1222-4a85-455b-a7a0-3ff9a9ef1573" xlink:href="lii-20240331.xsd#lii_A2025NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_62ac63e9-3d58-46dc-ae8b-88e13cf92a50" xlink:to="loc_lii_A2025NotesMember_290a1222-4a85-455b-a7a0-3ff9a9ef1573" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2027NotesMember_7c20c77b-3652-44ca-8d41-89278497dae5" xlink:href="lii-20240331.xsd#lii_A2027NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_62ac63e9-3d58-46dc-ae8b-88e13cf92a50" xlink:to="loc_lii_A2027NotesMember_7c20c77b-3652-44ca-8d41-89278497dae5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2023NotesMember_0934757d-8861-499f-8dd7-0e613e83463f" xlink:href="lii-20240331.xsd#lii_A2023NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_62ac63e9-3d58-46dc-ae8b-88e13cf92a50" xlink:to="loc_lii_A2023NotesMember_0934757d-8861-499f-8dd7-0e613e83463f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_A2028NotesMember_25778d8b-96db-4197-9c40-d340ee535a0d" xlink:href="lii-20240331.xsd#lii_A2028NotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_62ac63e9-3d58-46dc-ae8b-88e13cf92a50" xlink:to="loc_lii_A2028NotesMember_25778d8b-96db-4197-9c40-d340ee535a0d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_DebtInstrumentSeriesOfDebtNotes_128b222d-9daa-4b9d-83e7-b5d5a5a25fe5" xlink:href="lii-20240331.xsd#lii_DebtInstrumentSeriesOfDebtNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d6f5f927-07bf-4abc-8dfd-000fcdd40340" xlink:to="loc_lii_DebtInstrumentSeriesOfDebtNotes_128b222d-9daa-4b9d-83e7-b5d5a5a25fe5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_2a3ad4b6-8f42-41b8-858d-d2299abf83a5" 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_d6f5f927-07bf-4abc-8dfd-000fcdd40340" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_2a3ad4b6-8f42-41b8-858d-d2299abf83a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_aad652f4-7131-4dc7-8063-ea315e0e2a8b" 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_d6f5f927-07bf-4abc-8dfd-000fcdd40340" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_aad652f4-7131-4dc7-8063-ea315e0e2a8b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization_98a45587-8f0d-4d4e-af54-f671f4ea4b44" xlink:href="lii-20240331.xsd#lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d6f5f927-07bf-4abc-8dfd-000fcdd40340" xlink:to="loc_lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization_98a45587-8f0d-4d4e-af54-f671f4ea4b44" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_PeriodForRescissionOfAcceleratedDebt_71611a6b-a2ce-40a0-a8e5-de1654fa766d" xlink:href="lii-20240331.xsd#lii_PeriodForRescissionOfAcceleratedDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_d6f5f927-07bf-4abc-8dfd-000fcdd40340" xlink:to="loc_lii_PeriodForRescissionOfAcceleratedDebt_71611a6b-a2ce-40a0-a8e5-de1654fa766d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_11dae137-3948-40d1-ada7-9c7249971fc0" 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_d6f5f927-07bf-4abc-8dfd-000fcdd40340" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_11dae137-3948-40d1-ada7-9c7249971fc0" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/ComprehensiveIncomeLossReclassificationoutofAOCLDetails" xlink:type="simple" xlink:href="lii-20240331.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_daf94b8a-035b-4e60-962a-a79020922a5c" 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_27e81658-d96a-4f24-b11a-dd52b6922c08" 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_daf94b8a-035b-4e60-962a-a79020922a5c" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_27e81658-d96a-4f24-b11a-dd52b6922c08" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_e76842d5-402e-4d13-bf6d-a35a42a7f876" 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_27e81658-d96a-4f24-b11a-dd52b6922c08" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_e76842d5-402e-4d13-bf6d-a35a42a7f876" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_e76842d5-402e-4d13-bf6d-a35a42a7f876_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_e76842d5-402e-4d13-bf6d-a35a42a7f876" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_e76842d5-402e-4d13-bf6d-a35a42a7f876_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_e6bcbbc9-6b52-4b0a-b96b-330c378d6451" 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_e76842d5-402e-4d13-bf6d-a35a42a7f876" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_e6bcbbc9-6b52-4b0a-b96b-330c378d6451" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_c4e490d1-e9b0-4f93-8667-b0990d710367" 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_e6bcbbc9-6b52-4b0a-b96b-330c378d6451" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_c4e490d1-e9b0-4f93-8667-b0990d710367" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_f80275ee-7d42-432b-97a0-9422437fe85d" 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_27e81658-d96a-4f24-b11a-dd52b6922c08" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_f80275ee-7d42-432b-97a0-9422437fe85d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_f80275ee-7d42-432b-97a0-9422437fe85d_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_f80275ee-7d42-432b-97a0-9422437fe85d" xlink:to="loc_us-gaap_EquityComponentDomain_f80275ee-7d42-432b-97a0-9422437fe85d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_0b8a129e-126b-4d7f-bb2a-60c8cd8a9fac" 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_f80275ee-7d42-432b-97a0-9422437fe85d" xlink:to="loc_us-gaap_EquityComponentDomain_0b8a129e-126b-4d7f-bb2a-60c8cd8a9fac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_d514b295-551b-4349-b1dc-a3272317115c" 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_0b8a129e-126b-4d7f-bb2a-60c8cd8a9fac" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_d514b295-551b-4349-b1dc-a3272317115c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_9baa857e-0a09-4153-8741-5025bc289354" 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_0b8a129e-126b-4d7f-bb2a-60c8cd8a9fac" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_9baa857e-0a09-4153-8741-5025bc289354" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_a9ba2c51-89bb-471f-95ab-a5c6989ab7f6" 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_0b8a129e-126b-4d7f-bb2a-60c8cd8a9fac" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_a9ba2c51-89bb-471f-95ab-a5c6989ab7f6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_fa395070-00bb-4d85-91b3-c99ece4e7de2" 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_27e81658-d96a-4f24-b11a-dd52b6922c08" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_fa395070-00bb-4d85-91b3-c99ece4e7de2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_fa395070-00bb-4d85-91b3-c99ece4e7de2_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_fa395070-00bb-4d85-91b3-c99ece4e7de2" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_fa395070-00bb-4d85-91b3-c99ece4e7de2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_cca31ca3-b5f9-4f07-9b56-7e4bd096bb76" 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_fa395070-00bb-4d85-91b3-c99ece4e7de2" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_cca31ca3-b5f9-4f07-9b56-7e4bd096bb76" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommodityContractMember_a60ca08a-aa33-4ae2-b515-33649713ddce" 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_cca31ca3-b5f9-4f07-9b56-7e4bd096bb76" xlink:to="loc_us-gaap_CommodityContractMember_a60ca08a-aa33-4ae2-b515-33649713ddce" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_8e86fc27-3188-48a5-900c-951521f1db15" 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_daf94b8a-035b-4e60-962a-a79020922a5c" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_8e86fc27-3188-48a5-900c-951521f1db15" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_48848cfa-e2a1-4110-bf72-ea854bc47950" 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_daf94b8a-035b-4e60-962a-a79020922a5c" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_48848cfa-e2a1-4110-bf72-ea854bc47950" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_b5d00cd3-c27a-4402-a735-cd0b0bf910b5" 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_daf94b8a-035b-4e60-962a-a79020922a5c" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_b5d00cd3-c27a-4402-a735-cd0b0bf910b5" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/ComprehensiveIncomeLossChangesinAOCLDetails" xlink:type="simple" xlink:href="lii-20240331.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_1b11270e-3f50-44d6-920b-d5c4ff23cf44" 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_0e31b499-c3bd-479a-9437-73bc45d68c8e" 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_1b11270e-3f50-44d6-920b-d5c4ff23cf44" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_0e31b499-c3bd-479a-9437-73bc45d68c8e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_031e8ec6-6b00-4ea1-b82f-7f97f5b62463" 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_0e31b499-c3bd-479a-9437-73bc45d68c8e" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_031e8ec6-6b00-4ea1-b82f-7f97f5b62463" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_031e8ec6-6b00-4ea1-b82f-7f97f5b62463_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_031e8ec6-6b00-4ea1-b82f-7f97f5b62463" xlink:to="loc_us-gaap_EquityComponentDomain_031e8ec6-6b00-4ea1-b82f-7f97f5b62463_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_92774e89-4710-4ca1-9218-ea96b1ba522b" 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_031e8ec6-6b00-4ea1-b82f-7f97f5b62463" xlink:to="loc_us-gaap_EquityComponentDomain_92774e89-4710-4ca1-9218-ea96b1ba522b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_8971a9a9-e001-4a44-9209-a2d012746729" 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_92774e89-4710-4ca1-9218-ea96b1ba522b" xlink:to="loc_us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember_8971a9a9-e001-4a44-9209-a2d012746729" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_e501335d-bf19-4ca8-a913-c7fbb2f14190" 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_92774e89-4710-4ca1-9218-ea96b1ba522b" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_e501335d-bf19-4ca8-a913-c7fbb2f14190" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_c6716437-c661-47c8-83eb-e1e7c17a65e8" 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_92774e89-4710-4ca1-9218-ea96b1ba522b" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_c6716437-c661-47c8-83eb-e1e7c17a65e8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_efd4f0e8-c21f-494c-87ed-c31529fd1ded" 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_92774e89-4710-4ca1-9218-ea96b1ba522b" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_efd4f0e8-c21f-494c-87ed-c31529fd1ded" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentAttributableToNoncontrollingInterestMember_ca37e695-bfe0-4488-8561-372103990c4c" 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_92774e89-4710-4ca1-9218-ea96b1ba522b" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentAttributableToNoncontrollingInterestMember_ca37e695-bfe0-4488-8561-372103990c4c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward_858d5f4b-7ec2-4d7d-9898-3e162c47862c" xlink:href="lii-20240331.xsd#lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_1b11270e-3f50-44d6-920b-d5c4ff23cf44" xlink:to="loc_lii_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxRollForward_858d5f4b-7ec2-4d7d-9898-3e162c47862c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_4b5ebea5-141d-44ac-88f2-e220b2dcd7c4" 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_858d5f4b-7ec2-4d7d-9898-3e162c47862c" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_4b5ebea5-141d-44ac-88f2-e220b2dcd7c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_169b6148-f2a3-43e8-821d-f9d28f27fb1f" 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_858d5f4b-7ec2-4d7d-9898-3e162c47862c" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_169b6148-f2a3-43e8-821d-f9d28f27fb1f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_20cf047f-9307-4909-a39a-b9cb95a62b3a" 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_858d5f4b-7ec2-4d7d-9898-3e162c47862c" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_20cf047f-9307-4909-a39a-b9cb95a62b3a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_18235b65-bf33-40a4-98fc-c3006c32ed2d" 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_858d5f4b-7ec2-4d7d-9898-3e162c47862c" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_18235b65-bf33-40a4-98fc-c3006c32ed2d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_e2164e1a-3980-4901-9347-d06859b07751" 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-20240331.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_6d0d713d-f5bf-4971-ae62-951554d872ea" 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_75930e46-d3e5-4f12-b421-4486eb303a86" 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_6d0d713d-f5bf-4971-ae62-951554d872ea" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_75930e46-d3e5-4f12-b421-4486eb303a86" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_d39de5d4-f6ce-4c1f-af75-5d1ba9676f23" 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_75930e46-d3e5-4f12-b421-4486eb303a86" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_d39de5d4-f6ce-4c1f-af75-5d1ba9676f23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d39de5d4-f6ce-4c1f-af75-5d1ba9676f23_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_d39de5d4-f6ce-4c1f-af75-5d1ba9676f23" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d39de5d4-f6ce-4c1f-af75-5d1ba9676f23_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c43eb7d7-1f86-4c10-9646-27f97edb167e" 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_d39de5d4-f6ce-4c1f-af75-5d1ba9676f23" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c43eb7d7-1f86-4c10-9646-27f97edb167e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_7f8b2715-cd38-4c54-8c55-a4fa05694564" 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_c43eb7d7-1f86-4c10-9646-27f97edb167e" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_7f8b2715-cd38-4c54-8c55-a4fa05694564" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_fd6764ee-e815-424a-90d5-f25d938f7535" 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_75930e46-d3e5-4f12-b421-4486eb303a86" xlink:to="loc_us-gaap_DebtInstrumentAxis_fd6764ee-e815-424a-90d5-f25d938f7535" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_fd6764ee-e815-424a-90d5-f25d938f7535_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_fd6764ee-e815-424a-90d5-f25d938f7535" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_fd6764ee-e815-424a-90d5-f25d938f7535_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_516dad19-828b-4e0b-994d-0d2304974170" 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_fd6764ee-e815-424a-90d5-f25d938f7535" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_516dad19-828b-4e0b-994d-0d2304974170" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnsecuredDebtMember_04e52edd-e336-4dc4-a95f-eed79751aa4d" 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_516dad19-828b-4e0b-994d-0d2304974170" xlink:to="loc_us-gaap_UnsecuredDebtMember_04e52edd-e336-4dc4-a95f-eed79751aa4d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_036d18d8-3804-4615-83f4-8064f9f67e74" 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_6d0d713d-f5bf-4971-ae62-951554d872ea" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_036d18d8-3804-4615-83f4-8064f9f67e74" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFairValue_ee90c65a-2c8f-47d6-8813-952a220749fb" 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_036d18d8-3804-4615-83f4-8064f9f67e74" xlink:to="loc_us-gaap_DebtInstrumentFairValue_ee90c65a-2c8f-47d6-8813-952a220749fb" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.lennoxinternational.com/role/BusinessCombinationsandAssetAcquisitionsDetails" xlink:type="simple" xlink:href="lii-20240331.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_ab501743-76e8-4b60-a3d3-d195040aa91f" 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_81fbf31d-d8dc-4e0c-b1b0-06ce64c92ea3" 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_ab501743-76e8-4b60-a3d3-d195040aa91f" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_81fbf31d-d8dc-4e0c-b1b0-06ce64c92ea3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_4dc0b44f-b460-4323-a320-2b646aaef40e" 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_81fbf31d-d8dc-4e0c-b1b0-06ce64c92ea3" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_4dc0b44f-b460-4323-a320-2b646aaef40e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_4dc0b44f-b460-4323-a320-2b646aaef40e_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_4dc0b44f-b460-4323-a320-2b646aaef40e" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_4dc0b44f-b460-4323-a320-2b646aaef40e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d9de8ff2-19a6-468a-8a1d-00dda43483f6" 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_4dc0b44f-b460-4323-a320-2b646aaef40e" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d9de8ff2-19a6-468a-8a1d-00dda43483f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_AESMember_340ccc5c-ff15-4096-af1e-fc978d5cd6c2" xlink:href="lii-20240331.xsd#lii_AESMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d9de8ff2-19a6-468a-8a1d-00dda43483f6" xlink:to="loc_lii_AESMember_340ccc5c-ff15-4096-af1e-fc978d5cd6c2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedExcludingIntangibleAssetsNet_32b926dc-bb16-4c79-a277-e0a86458c924" xlink:href="lii-20240331.xsd#lii_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedExcludingIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ab501743-76e8-4b60-a3d3-d195040aa91f" xlink:to="loc_lii_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedExcludingIntangibleAssetsNet_32b926dc-bb16-4c79-a277-e0a86458c924" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_lii_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAssetsAndLiabilitiesAssumedExcludingIntangibleAssets_c9c45729-ad7d-488d-a299-24addebda861" xlink:href="lii-20240331.xsd#lii_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAssetsAndLiabilitiesAssumedExcludingIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_ab501743-76e8-4b60-a3d3-d195040aa91f" xlink:to="loc_lii_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentAssetsAndLiabilitiesAssumedExcludingIntangibleAssets_c9c45729-ad7d-488d-a299-24addebda861" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_e2353a5c-720b-4deb-b719-ea40eda0acf4" 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_ab501743-76e8-4b60-a3d3-d195040aa91f" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_e2353a5c-720b-4deb-b719-ea40eda0acf4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles_a073b2a5-65c7-4a92-8c2b-547b78d56df2" 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_ab501743-76e8-4b60-a3d3-d195040aa91f" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles_a073b2a5-65c7-4a92-8c2b-547b78d56df2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_3a80b169-b7d7-4159-b0c5-8e4bef2ca0d5" 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_ab501743-76e8-4b60-a3d3-d195040aa91f" xlink:to="loc_us-gaap_Goodwill_3a80b169-b7d7-4159-b0c5-8e4bef2ca0d5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_62a4be69-2824-4a83-bc10-eaceb3196a41" 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_ab501743-76e8-4b60-a3d3-d195040aa91f" xlink:to="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_62a4be69-2824-4a83-bc10-eaceb3196a41" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_ba9828a6-2d38-4287-8689-f918ba749c8f" 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_ab501743-76e8-4b60-a3d3-d195040aa91f" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet_ba9828a6-2d38-4287-8689-f918ba749c8f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentConsiderationTransferred_9f74972a-8e7b-4fce-8c9a-3817b9add182" 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_ab501743-76e8-4b60-a3d3-d195040aa91f" xlink:to="loc_us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentConsiderationTransferred_9f74972a-8e7b-4fce-8c9a-3817b9add182" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/AwardTypeOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#AwardTypeOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/AwardTypeOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_PerformanceSharesMember" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember" xlink:type="arc" order="5"/>
  </link:definitionLink>
</link:linkbase>
