Hartman Short Term Income Properties XX (HARXX) 10-K 2018 FY Annual report

EXHIBIT 32.1

CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO SECTION 906 OF THE

SARBANES-OXLEY ACT OF 2002

Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 and in connection with the Quarterly Report on Form 10-K of Hartman vREIT XXI, Inc. (the “Company”) for the year ended December 31, 2018, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), the undersigned, the Chief Executive Officer and President of the Company, certifies, to his knowledge, that:

(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 Company.

Date: April 1, 2019

/s/ Allen R. Hartman

Allen R. Hartman

Chairman of the Board and Chief Executive Officer

(Principal Executive Officer)