Exhibit 32.1
CertificatION
of Principal Executive Officer
Pursuant to 18 U.S.C. Section 1350,
as Adopted Pursuant to
Section 906 of the Sarbanes-Oxley Act of 2002
Solely
for the purposes of complying with 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, I, the
undersigned Principal Executive and Financial Officer of Flexible Solutions International, Inc. (the “Company”), hereby certify
that, to the best of my knowledge, the Quarterly Report on Form 10-Q of the Company for the quarter ended September 30,
| November 15, 2021 | /s/ Daniel B. O’Brien |
| Daniel B. O’Brien | |
| Principal Executive and Financial Officer |