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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-03-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000731766</issuerCik>
        <issuerName>UNITEDHEALTH GROUP INC</issuerName>
        <issuerTradingSymbol>UNH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001676672</rptOwnerCik>
            <rptOwnerName>REX JOHN F</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O UNITEDHEALTH GROUP INCORPORATED</rptOwnerStreet1>
            <rptOwnerStreet2>1 HEALTH DRIVE</rptOwnerStreet2>
            <rptOwnerCity>EDEN PRAIRIE</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55344</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President &amp; CFO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-03-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>75.994</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>186621.038</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>6791</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents dividend equivalents paid on outstanding restricted stock units. The dividend equivalents are subject to the same terms as the underlying restricted stock units and are forfeited if such units do not vest.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Faraz A. Choudhry, Attorney-in-Fact for John F. Rex</signatureName>
        <signatureDate>2025-03-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0508
4
2025-03-18
0
0000731766
UNITEDHEALTH GROUP INC
UNH
0001676672
REX JOHN F
C/O UNITEDHEALTH GROUP INCORPORATED
1 HEALTH DRIVE
EDEN PRAIRIE
MN
55344
0
1
0
0
President & CFO
0
Common Stock
2025-03-18
4
A
0
75.994
0
A
186621.038
D
Common Stock
6791
I
By Trust
Represents dividend equivalents paid on outstanding restricted stock units. The dividend equivalents are subject to the same terms as the underlying restricted stock units and are forfeited if such units do not vest.
Faraz A. Choudhry, Attorney-in-Fact for John F. Rex
2025-03-20