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

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2023-11-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001180162</rptOwnerCik>
            <rptOwnerName>HEMSLEY STEPHEN J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O UNITEDHEALTH GROUP INCORPORATED</rptOwnerStreet1>
            <rptOwnerStreet2>9900 BREN ROAD EAST</rptOwnerStreet2>
            <rptOwnerCity>MINNETONKA</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55343</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2023-11-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>G</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>22259</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>654027.942</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>335.6402</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By 401(k)</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>97176</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By GRAT10</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>50040</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By GRAT11</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>125000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By GRAT12</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>100000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By GRAT13</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Includes 104,174 shares transferred from Grantor Retained Annuity Trust #10 and 50,295 shares transferred from Grantor Retained Annuity Trust #11 to satisfy annuity payments on October 27, 2023.</footnote>
        <footnote id="F2">38,075 shares held by a trust are no longer reported herein as the reporting person has no reportable pecuniary interest in such shares. Note that previous filings made by the reporting person listed these shares as indirect holdings.</footnote>
        <footnote id="F3">On October 27, 2023, 104,174 UNH shares held in Grantor Retained Annuity Trust #10 were distributed to the reporting person to satisfy an annuity payment and are reported as directly owned as set forth in footnote 1.</footnote>
        <footnote id="F4">On October 27, 2023, 50,295 UNH shares held in Grantor Retained Annuity Trust #11 were distributed to the reporting person to satisfy an annuity payment and are reported as directly owned as set forth in footnote 1.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Faraz A. Choudhry, Attorney-in-Fact for Stephen J. Hemsley</signatureName>
        <signatureDate>2023-11-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0508
4
2023-11-16
0
0000731766
UNITEDHEALTH GROUP INC
UNH
0001180162
HEMSLEY STEPHEN J
C/O UNITEDHEALTH GROUP INCORPORATED
9900 BREN ROAD EAST
MINNETONKA
MN
55343
1
0
0
0
0
Common Stock
2023-11-16
4
G
0
22259
0
D
654027.942
D
Common Stock
335.6402
I
By 401(k)
Common Stock
97176
I
By GRAT10
Common Stock
50040
I
By GRAT11
Common Stock
125000
I
By GRAT12
Common Stock
100000
I
By GRAT13
Includes 104,174 shares transferred from Grantor Retained Annuity Trust #10 and 50,295 shares transferred from Grantor Retained Annuity Trust #11 to satisfy annuity payments on October 27, 2023.
38,075 shares held by a trust are no longer reported herein as the reporting person has no reportable pecuniary interest in such shares. Note that previous filings made by the reporting person listed these shares as indirect holdings.
On October 27, 2023, 104,174 UNH shares held in Grantor Retained Annuity Trust #10 were distributed to the reporting person to satisfy an annuity payment and are reported as directly owned as set forth in footnote 1.
On October 27, 2023, 50,295 UNH shares held in Grantor Retained Annuity Trust #11 were distributed to the reporting person to satisfy an annuity payment and are reported as directly owned as set forth in footnote 1.
Faraz A. Choudhry, Attorney-in-Fact for Stephen J. Hemsley
2023-11-20