<SEC-DOCUMENT>0001214659-21-007237.txt : 20210702
<SEC-HEADER>0001214659-21-007237.hdr.sgml : 20210702
<ACCEPTANCE-DATETIME>20210702163028
ACCESSION NUMBER:		0001214659-21-007237
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210630
FILED AS OF DATE:		20210702
DATE AS OF CHANGE:		20210702

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Castellaneta Andrew
		CENTRAL INDEX KEY:			0001627493

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-10551
		FILM NUMBER:		211070587

	MAIL ADDRESS:	
		STREET 1:		C/O OMNICOM GROUP INC.
		STREET 2:		437 MADISON AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			OMNICOM GROUP INC.
		CENTRAL INDEX KEY:			0000029989
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-ADVERTISING AGENCIES [7311]
		IRS NUMBER:				131514814
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		280 PARK AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017
		BUSINESS PHONE:		2124153600

	MAIL ADDRESS:	
		STREET 1:		280 PARK AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10017

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	OMNICOM GROUP INC
		DATE OF NAME CHANGE:	19920703

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	DOYLE DANE BERNBACH GROUP INC
		DATE OF NAME CHANGE:	19861117

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	DOYLE DANE BERNBACH INTERNATIONAL INC
		DATE OF NAME CHANGE:	19850604
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>marketforms-53338.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-06-30</periodOfReport>

    <issuer>
        <issuerCik>0000029989</issuerCik>
        <issuerName>OMNICOM GROUP INC.</issuerName>
        <issuerTradingSymbol>OMC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001627493</rptOwnerCik>
            <rptOwnerName>Castellaneta Andrew</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O OMNICOM GROUP INC.</rptOwnerStreet1>
            <rptOwnerStreet2>280 PARK AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10017</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>SVP, Chief Accounting Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.15 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2021-06-30</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5625</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>39084</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">These shares were acquired by the reporting person as a grant of restricted stock units (payable solely in common stock), which will vest 20% on August 15, 2022 and on each of the next four anniversaries thereof.</footnote>
        <footnote id="F2">Includes 3,177 shares acquired under Omnicom's employee stock purchase plan.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Michael J. O'Brien, Attorney in Fact for Andrew Castellaneta</signatureName>
        <signatureDate>2021-07-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
