<SEC-DOCUMENT>0001453687-21-000078.txt : 20210527
<SEC-HEADER>0001453687-21-000078.hdr.sgml : 20210527
<ACCEPTANCE-DATETIME>20210527180056
ACCESSION NUMBER:		0001453687-21-000078
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210526
FILED AS OF DATE:		20210527
DATE AS OF CHANGE:		20210527

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			TRABER PETER G
		CENTRAL INDEX KEY:			0001284500

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-37798
		FILM NUMBER:		21974716

	MAIL ADDRESS:	
		STREET 1:		430 THAMER LANE
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77025

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SELECTA BIOSCIENCES INC
		CENTRAL INDEX KEY:			0001453687
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		65 GROVE STREET
		CITY:			WATERTOWN
		STATE:			MA
		ZIP:			02472
		BUSINESS PHONE:		617-923-1400

	MAIL ADDRESS:	
		STREET 1:		65 GROVE STREET
		CITY:			WATERTOWN
		STATE:			MA
		ZIP:			02472
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_162215281637006.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-05-26</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001453687</issuerCik>
        <issuerName>SELECTA BIOSCIENCES INC</issuerName>
        <issuerTradingSymbol>SELB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001284500</rptOwnerCik>
            <rptOwnerName>TRABER PETER G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SELECTA BIOSCIENCES, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>65 GROVE STREET</rptOwnerStreet2>
            <rptOwnerCity>WATERTOWN</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02472</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Medical Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-05-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>20000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>3.9925</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>135500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported is a weighted average price. The shares were purchased in multiple transactions at per share prices ranging from $3.959 to $4.02. The Reporting Person undertakes to provide upon request to the SEC staff, the Issuer, or any stockholder of the Issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Matthew Bartholomae, Attorney-in-Fact for Peter G. Traber</signatureName>
        <signatureDate>2021-05-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
