<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-01-31</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000010456</issuerCik>
        <issuerName>BAXTER INTERNATIONAL INC</issuerName>
        <issuerTradingSymbol>BAX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001753950</rptOwnerCik>
            <rptOwnerName>Toth Christopher A.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>ONE BAXTER PARKWAY</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DEERFIELD</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60015</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP, Group Pres, Kidney Care</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, $1 par value</value>
            </securityTitle>
            <transactionDate>
                <value>2025-01-31</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>25372</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>32.56</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>105186</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Represents the number of shares forfeited by the reporting person to cover the withholding of taxes incurred as a result of the delivery of shares on January 31, 2025 from the settlement of restricted stock units granted on March 6, 2024.  These shares vested on January 31, 2025 in accordance with the terms of that Equity Purchase Agreement, dated as of August 12, 2024 (as amended), by and among Baxter International Inc. and certain Carlyle affiliates (the &quot;EPA&quot;).</footnote>
        <footnote id="F2">Adjusted to reflect (i) automatic reinvestment of dividends, and (ii) the number of shares forfeited by the reporting person in connection with the closing of the EPA, as further described in the Issuer's Form 8-K filed on February 3, 2025.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Kimberly Olson, as attorney in fact for Christopher A. Toth</signatureName>
        <signatureDate>2025-02-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
