TMUS · Quarterly Report (Form 10-Q) · Filed April 28, 2026

T-mobile US Inc — 10-Q exhibit

tmus03312026ex321.htm

Document

EXHIBIT 32.1

Certification of Chief Executive 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 Quarterly Report of T-Mobile US, Inc. (the “Company”), on Form 10-Q for the quarter ended March 31, 2026, as filed with the Securities and Exchange Commission (the “Report”), Srinivasan Gopalan, Chief Executive Officer of the Company, does hereby certify, pursuant to § 906 of the Sarbanes-Oxley Act of 2002 (18 U.S.C. § 1350), that to his knowledge:

1.The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

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

April 28, 2026


/s/ Srinivasan Gopalan
Srinivasan Gopalan Chief Executive Officer

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