<SEC-DOCUMENT>0001214659-21-000844.txt : 20210127
<SEC-HEADER>0001214659-21-000844.hdr.sgml : 20210127
<ACCEPTANCE-DATETIME>20210127093224
ACCESSION NUMBER:		0001214659-21-000844
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210106
FILED AS OF DATE:		20210127
DATE AS OF CHANGE:		20210127

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			GOULD FREDRIC H
		CENTRAL INDEX KEY:			0001187901

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-09279
		FILM NUMBER:		21557118

	MAIL ADDRESS:	
		STREET 1:		60 CUTTER MILL ROAD
		STREET 2:		SUITE 303
		CITY:			GREAT NECK
		STATE:			NY
		ZIP:			11021

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ONE LIBERTY PROPERTIES INC
		CENTRAL INDEX KEY:			0000712770
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		IRS NUMBER:				133147497
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		60 CUTTER MILL RD
		STREET 2:		SUITE 303
		CITY:			GREAT NECK
		STATE:			NY
		ZIP:			11021-3190
		BUSINESS PHONE:		5164663100

	MAIL ADDRESS:	
		STREET 1:		60 CUTTER MILL ROAD
		STREET 2:		SUITE 303
		CITY:			GREAT NECK
		STATE:			NY
		ZIP:			11021-3190

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ONE LIBERTY FIRESTONE PROPERTIES INC
		DATE OF NAME CHANGE:	19851112
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>marketforms-51208.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2021-01-06</periodOfReport>

    <dateOfOriginalSubmission>2021-01-08</dateOfOriginalSubmission>

    <issuer>
        <issuerCik>0000712770</issuerCik>
        <issuerName>ONE LIBERTY PROPERTIES INC</issuerName>
        <issuerTradingSymbol>OLP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001187901</rptOwnerCik>
            <rptOwnerName>GOULD FREDRIC H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>60 CUTTER MILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 303</rptOwnerStreet2>
            <rptOwnerCity>GREAT NECK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>11021</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>Vice Chairman of Board</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1894883.215</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Gould Investors L.P.</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Reporting person is the sole shareholder of the corporate managing general partner of Gould Investors L.P.  Reporting person also holds limited partnership interests in Gould Investors L.P., both directly and indirectly.  These shares represent all shares of the issuer owned by Gould Investors L.P. including shares in which reporting person does not have a pecuniary interest. Includes shares obtained through the issuer's dividend reinvestment plan.</footnote>
        <footnote id="F2">This Form 4A is filed to correct an error in Column 5 of reporting person's Form 4 filed January 8, 2021.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Fredric H. Gould by David Kalish, his attorney in fact</signatureName>
        <signatureDate>2021-01-27</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
