EX-32.1 6 a2227757zex-32_1.htm EX-32.1
QuickLinks -- Click here to rapidly navigate through this document

EXHIBIT 32.1

CERTIFICATION OF PRESIDENT AND CHIEF EXECUTIVE OFFICER

PURSUANT TO 18 U.S.C. SECTION 1350
(SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002)

The undersigned, Patrick J. Callan, Jr., does hereby certify to his knowledge, pursuant to 18 U.S.C. Section 1350 as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that based upon a review of the Annual Report on Form 10-K for the year ended December 31, 2015 of One Liberty Properties, Inc. ("the Registrant"), as filed with the Securities and Exchange Commission on the date hereof (the "Report"):

(1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

(2) The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Registrant.

Date: March 15, 2016 |  | /s/ PATRICK J. CALLAN, JR. Patrick J. Callan, Jr. President and Chief Executive Officer

QuickLinks

EXHIBIT 32.1

CERTIFICATION OF PRESIDENT AND CHIEF EXECUTIVE OFFICER
PURSUANT TO 18 U.S.C. SECTION 1350 (SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002)