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 the Quarterly Report on Form 10-Q of TransDigm Group Incorporated (the “Company”) for the quarter ended March 28, 2020 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Kevin Stein, President, Chief Executive Officer and Director (Principal Executive Officer), 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 and Exchange Act of 1934; and

2. The information contained in the Report fairly presents in all material respects, the financial condition of the Company as of the dates indicated and results of operations of the Company for the periods indicated.

Date: May 5, 2020

/s/ Kevin Stein

Name: Kevin Stein

Title: President, Chief Executive Officer and Director

(Principal Executive Officer)