<?xml version="1.0" encoding="utf-8"?>
<!--Generated by DFIN XBRL Instance Document - http://www.dfinsolutions.com/ - Version R3.0 - on 20-March-2024 [03:23:52] {PM}-->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:xbrldt="http://xbrl.org/2005/xbrldt">
<roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#IndividualsOnly" roleURI="http://xbrl.sec.gov/ecd/role/IndividualsOnly" />
<roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#PvpAdjustmentsOnly" roleURI="http://xbrl.sec.gov/ecd/role/PvpAdjustmentsOnly" />
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" />
<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" />
<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" />
<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" />
<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" />
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll" />
<definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/ecd/role/IndividualsOnly">
<loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#ecd_AllIndividualsMember" xlink:label="AllIndividualsMember" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_Mr.MaddoxMember" xlink:label="Mr.MaddoxMember" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllIndividualsMember" xlink:to="Mr.MaddoxMember" order="100" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_Mr.BillingsMember" xlink:label="Mr.BillingsMember" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllIndividualsMember" xlink:to="Mr.BillingsMember" order="101" />
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/ecd/role/PvpAdjustmentsOnly">
<loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/ecd/2023/ecd-2023.xsd#ecd_AllAdjToCompMember" xlink:label="AllAdjToCompMember" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_ChangeInFairValueOfEquityAwardsAtEitherTheVestingMember" xlink:label="ChangeInFairValueOfEquityAwardsAtEitherTheVestingMember" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="ChangeInFairValueOfEquityAwardsAtEitherTheVestingMember" order="102" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_ReversalOfCompensationActuallyPaidRelatedToTheForfeitureMember" xlink:label="ReversalOfCompensationActuallyPaidRelatedToTheForfeitureMember" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="ReversalOfCompensationActuallyPaidRelatedToTheForfeitureMember" order="103" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_AggregateGrantDateFairValueMember" xlink:label="AggregateGrantDateFairValueMember" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="AggregateGrantDateFairValueMember" order="104" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_AggregateGrantDateFairValueRemeasuredMember" xlink:label="AggregateGrantDateFairValueRemeasuredMember" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="AggregateGrantDateFairValueRemeasuredMember" order="105" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_AggregateGrantDateFairValueAChangeMember" xlink:label="AggregateGrantDateFairValueAChangeMember" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="AggregateGrantDateFairValueAChangeMember" order="106" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_GrantedPriorTo2022Member" xlink:label="GrantedPriorTo2022Member" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="GrantedPriorTo2022Member" order="107" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_GrantedPriorTo2022AndVestedIn2022Member" xlink:label="GrantedPriorTo2022AndVestedIn2022Member" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="GrantedPriorTo2022AndVestedIn2022Member" order="108" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_GrantedPriorTo2020AndVestedIn2020Member" xlink:label="GrantedPriorTo2020AndVestedIn2020Member" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="GrantedPriorTo2020AndVestedIn2020Member" order="109" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_GrantedPriorTo2020Member" xlink:label="GrantedPriorTo2020Member" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="GrantedPriorTo2020Member" order="110" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_GrantedPriorTo2020AndVestedIn20201Member" xlink:label="GrantedPriorTo2020AndVestedIn20201Member" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="GrantedPriorTo2020AndVestedIn20201Member" order="111" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_ReversalOfCompensationActuallyPaidRelatedToTheCancellationOfEquityAwardsGrantedMember" xlink:label="ReversalOfCompensationActuallyPaidRelatedToTheCancellationOfEquityAwardsGrantedMember" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="ReversalOfCompensationActuallyPaidRelatedToTheCancellationOfEquityAwardsGrantedMember" order="112" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_GrantedPriorTo2023Member" xlink:label="GrantedPriorTo2023Member" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="GrantedPriorTo2023Member" order="113" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_GrantedPriorTo2023AndVestedIn2023Member" xlink:label="GrantedPriorTo2023AndVestedIn2023Member" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="GrantedPriorTo2023AndVestedIn2023Member" order="114" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_OptionAwardsGrantedDuring2022WithAnAggregateGrantDateFairValueMember" xlink:label="OptionAwardsGrantedDuring2022WithAnAggregateGrantDateFairValueMember" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="OptionAwardsGrantedDuring2022WithAnAggregateGrantDateFairValueMember" order="115" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_GrantedPriorTo2022AndVestedIn20221Member" xlink:label="GrantedPriorTo2022AndVestedIn20221Member" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="GrantedPriorTo2022AndVestedIn20221Member" order="116" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_AggregateGrantDateFairValueRemeasured1Member" xlink:label="AggregateGrantDateFairValueRemeasured1Member" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="AggregateGrantDateFairValueRemeasured1Member" order="117" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_AggregateGrantDateFairValue1Member" xlink:label="AggregateGrantDateFairValue1Member" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="AggregateGrantDateFairValue1Member" order="118" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_GrantedPriorTo2021AndVestedIn2021Member" xlink:label="GrantedPriorTo2021AndVestedIn2021Member" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="GrantedPriorTo2021AndVestedIn2021Member" order="119" />
<loc xlink:type="locator" xlink:href="wynn-20231231.xsd#wynn_GrantedPriorTo2021Member" xlink:label="GrantedPriorTo2021Member" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllAdjToCompMember" xlink:to="GrantedPriorTo2021Member" order="120" />
</definitionLink>
</linkbase>
