EXHIBIT 32.1

CERTIFICATION OF

CHIEF EXECUTIVE OFFICER AND CHIEF FINANCIAL OFFICER

PURSUANT TO 18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES‑OXLEY ACT OF 2002

In connection with the annual report on Annual Report on Form 10-K of FormFactor, Inc., a Delaware corporation, for the period ended December 30, 2017, as filed with the Securities and Exchange Commission, each of the undersigned officers of FormFactor, Inc. certifies pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes‑Oxley Act of 2002, that, to his respective knowledge:

(1) the annual 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 annual report fairly presents, in all material respects, the financial condition and results of operations of FormFactor, Inc. for the periods presented therein.

Date:	February 27, 2018	/s/ MICHAEL D. SLESSOR
		Michael D. Slessor Chief Executive Officer (Principal Executive Officer and Director)
Date:	February 27, 2018	/s/ MICHAEL M. LUDWIG
		Michael M. Ludwig Chief Financial Officer (Principal Financial Officer and Principal Accounting Officer)