Houghton Mifflin Harcourt (HMHC) 10-Q 2018 Q3 Quarterly 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

In connection with Houghton Mifflin Harcourt Company’s (the “Company”) Quarterly Report on Form10-Q for the three months ended September 30, 2018, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, John J. Lynch, Jr., President and Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to my knowledge:

(1) 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

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

Date: November 8, 2018

By:	/s/ John J. Lynch, Jr.
	John J. Lynch, Jr. President and Chief Executive Officer