AT&T Mobility, LLC, also known as AT&T Wireless and marketed as simply AT&T, is an American telecommunications company. It is a wholly owned subsidiary of AT&T Inc. and provides wireless services in the United States. AT&T Mobility is the largest wireless carrier in the United States, with 241.5 million subscribers as of December 31, 2023.

AT&T Inc. is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's fourth-largest telecommunications company by revenue and the largest wireless carrier in the United States. As of 2023, AT&T was ranked 13th on the Fortune 500 rankings of the largest United States corporations, with revenues of $120.7 billion.