EX-32.1 8 ex_912918.htm EXHIBIT 32.1

Exhibit 32.1

CERTIFICATION

I, Celeste B. Mastin, in connection with the Quarterly Report of H.B. Fuller Company on Form 10-Q for the quarter ended February 28, 2026 (the “Report”), hereby certify that:

| (a) | the Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m or 78o(d)), and

| (b) | the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of H.B. Fuller Company.

Date: March 26, 2026

/s/ Celeste B. Mastin |
Celeste B. Mastin President and Chief Executive Officer |