Exhibit 5.1

AMERICAS NEW YORK SAN FRANCISCO SÃO PAULO SILICON VALLEY WASHINGTON, D.C. ASIA BEIJING HONG KONG SEOUL	One Liberty Plaza New York, NY 10006-1470 T: +1 212 225 2000 F: +1 212 225 3999 clearygottlieb.com D: +1 212 225 2286 afleisher@cgsh.com	EUROPE & MIDDLE EAST ABU DHABI BRUSSELS COLOGNE FRANKFURT LONDON MILAN PARIS ROME

May 6, 2024

T-Mobile US, Inc.

12920 SE 38th Street

Bellevue, Washington 98006

Ladies and Gentlemen:

We have acted as special counsel to T-Mobile US, Inc., a corporation organized under the laws of Delaware (the “Company”), in connection with the preparation and filing with the Securities and Exchange Commission (the “Commission”) of the Company’s registration statement on Form S-3 (including the documents incorporated by reference therein, the “Registration Statement”) pursuant to the Securities Act of 1933, as amended (the “Securities Act”), relating to the offering from time to time by the selling stockholders contemplated thereby (the “Selling Stockholders”) of shares of the Company’s common stock, par value $0.00001 per share (the “Securities”). The Securities being registered under the Registration Statement will have an indeterminate aggregate initial offering price and will be offered on a continuous or delayed basis pursuant to the provisions of Rule 415 under the Securities Act.

In arriving at the opinions expressed below, we have reviewed the following documents:

(a) the Registration Statement; and

(b) the Amended and Restated Certificate of Incorporation of the Company, certified by the Secretary of State of the State of Delaware.

In addition, we have reviewed the originals or copies certified or otherwise identified to our satisfaction of all such corporate records of the Company and such other documents, and we have made such investigations of law, as we have deemed appropriate as a basis for the opinions expressed below.

In rendering the opinions expressed below, we have assumed the authenticity of all documents submitted to us as originals and the conformity to the originals of all documents submitted to us as copies. In addition, we have assumed and have not verified the accuracy as to factual matters of each document we have reviewed.

Based on the foregoing and subject to the further assumptions and qualifications set forth below, it is our opinion that the Securities to be offered and sold by the Selling Stockholders are validly issued by the Company and fully paid and nonassessable.

In rendering the opinion above, we have assumed that (i) the Securities will be offered, sold and delivered in compliance with applicable law and in the manner contemplated by the Registration Statement and (ii) the Securities will be offered, sold and delivered to, and paid for by, the purchasers thereof at the price specified in, and in accordance with the terms of, an agreement or agreements duly authorized, executed and delivered by the parties thereto.

Cleary Gottlieb Steen & Hamilton LLP or an affiliated entity has an office in each of the locations listed above.

T-Mobile US, Inc., p. 2

The foregoing opinion is limited to the General Corporation Law of the State of Delaware, including the applicable provisions of the Delaware Constitution and reported judicial decisions interpreting such laws.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement and to the reference to this firm under the heading “Legal Matters” in the Registration Statement and the related prospectus included in the Registration Statement. In giving such consent, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission thereunder.

Very truly yours,
CLEARY GOTTLIEB STEEN & HAMILTON LLP
By	/s/ Adam Fleisher
	Adam Fleisher, a Partner