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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-06-29</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000726728</issuerCik>
        <issuerName>REALTY INCOME CORP</issuerName>
        <issuerTradingSymbol>O</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001206775</rptOwnerCik>
            <rptOwnerName>PFEIFFER MICHAEL R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>11995 EL CAMINO REAL</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN DIEGO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92130</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP, Chief Admin. Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-06-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2428</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>48552</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-06-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1307</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>67.95</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>47245</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-06-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4830</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>66.74</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>42415</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Restricted stock units granted through an incentive plan; no consideration was paid. The restricted stock units vest immediately at the time of grant and were made issuable in the form of common stock.</footnote>
        <footnote id="F2">Represents shares automatically withheld upon the issuance of 2,428 shares of common stock on June 29, 2021, which amount is determined based upon the greater of such holder's minimum required tax withholding rate or the highest withholding rate permitted under the rules of the applicable taxing authority for tax withholding.</footnote>
        <footnote id="F3">As noted in Realty Income Corporation's 8-K filed January 26, 2021 the issuer retired as an executive effective June 30, 2021, at which time all unvested restricted stock units became vested. As such, amount represents shares automatically withheld upon the issuance of 9,159 shares of common stock on June 30, 2021, which amount is determined based upon the greater of such holder's minimum required tax withholding rate or the highest withholding rate permitted under the rules of the applicable taxing authority for tax withholding.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Michael R. Pfeiffer</signatureName>
        <signatureDate>2021-07-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0306
4
2021-06-29
1
0000726728
REALTY INCOME CORP
O
0001206775
PFEIFFER MICHAEL R
11995 EL CAMINO REAL
SAN DIEGO
CA
92130
0
1
0
0
EVP, Chief Admin. Officer
Common Stock
2021-06-29
4
A
0
2428
0.0
A
48552
D
Common Stock
2021-06-29
4
F
0
1307
67.95
D
47245
D
Common Stock
2021-06-30
4
F
0
4830
66.74
D
42415
D
Restricted stock units granted through an incentive plan; no consideration was paid. The restricted stock units vest immediately at the time of grant and were made issuable in the form of common stock.
Represents shares automatically withheld upon the issuance of 2,428 shares of common stock on June 29, 2021, which amount is determined based upon the greater of such holder's minimum required tax withholding rate or the highest withholding rate permitted under the rules of the applicable taxing authority for tax withholding.
As noted in Realty Income Corporation's 8-K filed January 26, 2021 the issuer retired as an executive effective June 30, 2021, at which time all unvested restricted stock units became vested. As such, amount represents shares automatically withheld upon the issuance of 9,159 shares of common stock on June 30, 2021, which amount is determined based upon the greater of such holder's minimum required tax withholding rate or the highest withholding rate permitted under the rules of the applicable taxing authority for tax withholding.
Michael R. Pfeiffer
2021-07-01