<SEC-DOCUMENT>0000912593-20-000168.txt : 20201106
<SEC-HEADER>0000912593-20-000168.hdr.sgml : 20201106
<ACCEPTANCE-DATETIME>20201106143545
ACCESSION NUMBER:		0000912593-20-000168
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20201030
FILED AS OF DATE:		20201106
DATE AS OF CHANGE:		20201106

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			UNDERWOOD BAXTER
		CENTRAL INDEX KEY:			0001444689

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12616
		FILM NUMBER:		201293880

	MAIL ADDRESS:	
		STREET 1:		450 SOUTH ORANGE AVENUE
		CITY:			ORLANDO
		STATE:			FL
		ZIP:			32801

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SUN COMMUNITIES INC
		CENTRAL INDEX KEY:			0000912593
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		IRS NUMBER:				382730780
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		27777 FRANKLIN ROAD
		STREET 2:		SUITE 200
		CITY:			SOUTHFIELD
		STATE:			MI
		ZIP:			48034
		BUSINESS PHONE:		2482082500

	MAIL ADDRESS:	
		STREET 1:		27777 FRANKLIN ROAD
		STREET 2:		SUITE 200
		CITY:			SOUTHFIELD
		STATE:			MI
		ZIP:			48034
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>wf-form3_160469132791882.xml
<DESCRIPTION>FORM 3
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2020-10-30</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000912593</issuerCik>
        <issuerName>SUN COMMUNITIES INC</issuerName>
        <issuerTradingSymbol>SUI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001444689</rptOwnerCik>
            <rptOwnerName>UNDERWOOD BAXTER</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>14785 PRESTON ROAD, 9TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75254</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO - Safe Harbor Marinas, LLC</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>COMMON STOCK, $0.01 PAR VALUE</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>69368</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>SERIES H PREFERRED OPERATING PARTNERSHIP UNITS</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>COMMON STOCK, $0.01 PAR VALUE</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>18850.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>SERIES H PREFERRED OPERATING PARTNERSHIP UNITS</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>COMMON STOCK, $0.01 PAR VALUE</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>37623.0</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Issued by the Issuer's operating partnership, Sun Communities Operating Limited Partnership.</footnote>
        <footnote id="F2">Each Series H Preferred OP Unit can be exchanged for a number of shares of the Issuer's common stock equal to the quotient obtained by dividing $100.00 by $164.00 (as such ratio is subject to adjustments for certain capital events) at the holder's option and have no expiration date.</footnote>
        <footnote id="F3">Owned by a family limited partnership. The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Baxter R. Underwood</signatureName>
        <signatureDate>2020-11-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
