| T. Rowe Price | business, enterprise, public company | Baltimore | 1937 |
| Tablet | podcast production company, online magazine | Manhattan | June 2009 |
| Tandem Computers | manufacturing company, business | Cupertino | 1974 |
| Tarleton State University | public educational institution of the United States, university | — | 1896 |
| TASCAM | business | Tokyo | 1971 |
| Taylorcraft Aircraft | aerospace manufacturer | Brownsville | 1935 |
| TaylorMade Golf Company | business | Carlsbad | 1979 |
| Tazo | business | Portland | 1994 |
| TBWA Worldwide | business | New York City | 1970 |
| TD Ameritrade | business, enterprise, public company | Omaha | 1971 |
| Teledyne Technologies | business, conglomerate, public company | Thousand Oaks | 1960 |
| Temple Hill Entertainment | film production company | Los Angeles | 2002 |
| Tennessee State University | historically black college or university, public educational institution of the United States, school, land-grant university, public university | — | 1912 |
| Tennessee Technological University | public educational institution of the United States, public university | — | 1915 |
| Tennessee Valley Authority | electricity supply company, independent agency of the United States government, business | Knoxville | 1933 |
| Terex | public company | Westport | 1925 |
| Tesla Energy | corporation, brand, organization, business, company | Fremont | — |
| Tesoro Corporation | business, gas station chain, enterprise, public company | — | 1968 |
| Texas Christian University | church college, private not-for-profit educational institution, Christian school, private university | Fort Worth | 1873 |
| Texas Southern University | historically black college or university, public educational institution of the United States, school, university | — | 1947 |
| Texas State University | public educational institution of the United States, Hispanic-serving institution, public university | — | 1899 |
| Thatgamecompany | video game developer | Santa Monica | May 15, 2006 |
| The 3DO Company | video game publisher, video game console manufacturer, video game developer | Redwood City | September 12, 1991 |
| The Asylum | film production company, film distributor, film studio | Hollywood, Los Angeles | 1997 |
| The Athletic | online newspaper, podcast network, business, sports journalism | San Francisco | January 2016 |
| The Atlantic | news website, website, magazine, business | Washington, D.C. | 1857 |
| The Avery Coonley School | school building, school | — | 1906 |
| The Bank of New York Mellon | business, enterprise | New York City | 2007 |
| The Beverly Hilton | hotel | — | 1955 |
| The Biltmore Los Angeles | hotel | — | 1923 |
| The Bitter End | concert hall, café, nightclub | — | 1961 |
| The Catholic University of America | Catholic university | — | 1887 |
| The Cheesecake Factory | restaurant chain, public company | Calabasas | 1978 |
| The Cigna Group | business, enterprise, public company | Bloomfield | 1982 |
| The Collective | video game developer | Newport Beach | 1997 |
| The Fletcher School of Law and Diplomacy | law school, university | Medford | 1933 |
| The Hershey Company | business, enterprise, public company | Hershey | 1894 |
| The Hertz Corporation | car rental company, business, enterprise, public company | Estero | 1918 |
| The Home Depot | hardware store chain, business, public company | Cobb County | 1978 |
| The Learning Company | video game developer | Cedar Rapids, San Francisco | 1980 |
| The Linq | casino, hotel | — | 2014 |
| The McClatchy Company | publishing house, business, public company | Sacramento | 1857 |
| The Mirisch Company | film production company | Los Angeles | 1957 |
| The Mosaic Company | business, public company | Plymouth | 2004 |
| The Muppets Studio | business | Los Angeles | 2004 |
| The New School | research university, private not-for-profit educational institution, educational institution, open-access publisher, private university | — | 1919 |
| The New Yorker | news magazine, publishing house, website, magazine, production team | New York City | February 21, 1925 |
| The NPD Group | business, enterprise | Port Washington | 1967 |
| The Onion | monthly newspaper, weekly newspaper, business | Chicago | 1988 |
| The Public Theater | theatre company, nonprofit organization | New York City | 1954 |
| The Rockefeller University | biological research institute, private not-for-profit educational institution, private university | New York City | 1901 |
| The Salt Lake Tribune | newspaper, 501(c)(3) organization, business | — | 1870 |
| The Travelers Companies | business, enterprise, public company | New York City | 1853 |
| The University of Texas MD Anderson Cancer Center | hospital, public educational institution of the United States, university | Houston | 1941 |
| The University of the Arts | private not-for-profit educational institution, university | Philadelphia | 1987 |
| The Vanderpump Hotel Las Vegas | hotel | — | March 2, 1979 |
| The Venetian | skyscraper, casino, hotel | — | 1997 |
| The Walt Disney Company | film production company, media conglomerate, commercial organization, business, public company | Burbank | October 16, 1923 |
| The Wharton School | business school, private university | Philadelphia | 1881 |
| The Willy Wonka Candy Company | food manufacturer, chocolaterie | Chicago | 1971 |
| Theranos | enterprise, company | Palo Alto | 2003 |
| Thermo Fisher Scientific Inc. | business, enterprise, public company | Waltham | 2006 |
| Thermos L.L.C. | manufacturing company | Chicago, Minato | 1980 |
| ThinkFilm | film industry, film production company, film distributor | New York City | September 2001 |
| Thiokol | business, defunct organization | Trenton, Brigham City | 1929 |
| Thomas Built Buses | automobile manufacturer | High Point | 1972 |
| Thomas Edison State University | public educational institution of the United States, school, academic institution | — | 1972 |
| THQ | video game publisher, video game developer, public company | Agoura Hills, California | 1990 |
| THX | technical standard, business | San Rafael | 1983 |
| TIAA | insurance company, business | New York City | 1918 |
| Tibco Software | business, enterprise, public company | Palo Alto | 1997 |
| Tiffany & Co. | jewelry shop chain, business, public company | New York City | 1837 |
| Tiger Electronics | business, subsidiary company | Vernon Hills | 1978 |
| Tilted Mill Entertainment | video game developer | Framingham | 2001 |
| Time Inc. | business, enterprise | New York City | November 28, 1922 |
| Time Warner Cable | internet service provider, production company, business, enterprise, public company | New York City | 1989 |
| Timex Group USA | business | Middlebury, United States | 1854 |
| Titleist | business | Fairhaven | 1932 |
| TKO Group Holdings | business, company | New York City | September 12, 2023 |
| Tommy Hilfiger B.V. | privately held company, business, subsidiary company, enterprise, brick and mortar | New York City, Amsterdam | 1985 |
| Tor Books | book publisher, publishing house, imprint | Equitable Building | 1980 |
| Toro | business, enterprise, public company | Bloomington | 1914 |
| Total Nonstop Action Wrestling | business, enterprise, professional wrestling promotion | Nashville | January 4, 2024 |
| Touchstone Television | business | California | December 4, 2014 |
| Tower Records | business, chain | Sacramento | 1960 |
| Toys for Bob | video game developer | Novato | 1989 |
| Trader Joe's | supermarket chain, business, gourmet supermarket chain | Monrovia | 1958 |
| Trans Executive Airlines | airline | Honolulu | 1982 |
| Trans States Airlines | airline | United States, Bridgeton | 1985 |
| Trans World Airlines | airline | Fort Worth | 1926 |
| Transylvania University | private not-for-profit educational institution, private university | Lexington | 1780 |
| TriBeCa Productions | television production company, film production company | New York City | 1989 |
| Tribune Publishing | publishing house | Chicago | 2014 |
| Trimark Pictures | film production company, business | Santa Monica | 1985 |
| Trimble | business, enterprise, public company | Westminster | 1978 |
| Trinity Evangelical Divinity School | university | — | 1950 |
| Tripadvisor | travel website, website, business, enterprise, public company | Needham | February 14, 2000 |
| Tropicana Las Vegas | skyscraper, casino, hotel, music venue | — | 1957 |
| Trump International Hotel and Tower | skyscraper, hotel | — | 2009 |
| Trump Mobile | mobile virtual network operator, brand | — | June 16, 2025 |
| Trump Shuttle | airline | New York City | 1989 |
| Trump Steaks | business | New York City | May 8, 2007 |
| Trump University | business | New York City | 2005 |
| Tseng Labs | business, defunct organization | Pennsylvania | 1983 |
| Tulane University | private not-for-profit educational institution, university | New Orleans | 1834 |
| Turner Broadcasting System | production company, media company, business, enterprise | CNN Center | 1970 |
| Turnitin | website, business, anti-plagiarism software | Oakland | 1997 |
| Twilio | website, business, company, public company | San Francisco | 2008 |
| Two Steps from Hell | musical group, music organization, business, enterprise | Los Angeles | 2006 |