Global Blood Therapeutics (GBT) 10-Q 2018 Q2 Quarterly report

Exhibit 32.1

GLOBAL BLOOD THERAPEUTICS, INC.

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 the Quarterly Report of Global Blood Therapeutics, Inc. (the “Company”) on Form10-Q for the quarter ended June 30, 2018, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Ted W. Love, President and Chief Executive Officer of the Company, and Jeffrey Farrow, Chief Financial Officer, do each hereby 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, 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.

/s/ Ted W. Love, M.D.

Ted W. Love, M.D.

President and Chief Executive Officer

(Principal Executive Officer)

August 2, 2018

/s/ Jeffrey Farrow

Jeffrey Farrow

Chief Financial Officer

(Principal Financial Officer)

August 2, 2018

This certification accompanies the Form10-Q to which it relates, is not deemed filed with the Securities and Exchange Commission and is not to be incorporated by reference into any filing of Global Blood Therapeutics, Inc. under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended (whether made before or after the date of the Form10-Q), irrespective of any general incorporation language contained in such filing.