T
- Taft Broadcasting – Charles Phelps Taft
- TAG Heuer – Eduardo Heuer
- Tamiya – Yoshio Tamiya
- Tandy Corporation - Dave L. Tandy
- Tanfoglio – Tanfoglio Giuseppe
- Taser International – Thomas A. Swift's Electric Rifle
- Tata – Jamsetji Tata
- Tate & Lyle - Henry Tate and Abram Lyle
- Taylor Woodrow - Frank Taylor and Jack Woodrow
- Team Goh – Kazimuchi Goh
- Team LCR – Lucio Cecchinello
- Ten Kate Racing – Gerrit ten Kate, named after his nephew Ronald's motorcycle dealership Ten Kate Motorcycles
- Terrytoons - Paul Terry
- Tesco – amalgamation of TES (from T. E. Stockwell) and CO (from Jack Cohen)
- Tesla Motors – named in honor of Nikola Tesla
- Testor Corporation – Nils Testor
- Thomas B. Jeffery Company – Thomas B. Jeffery
- Thomas Cook Group, Thomas Cook Airlines – Thomas Cook
- Various named after Elihu Thomson:
- Alstom
- Thomson SA (now Technicolor SA)
- Thomson-CSF (now Thales Group)
- Thomson-Houston Electric Company (now General Electric)
- The Thomson Corporation – Roy Thomson, 1st Baron Thomson of Fleet
- Thorn Electrical Industries - Jules Thorn
- Thorntons (British chocolatier) - Joseph William Thornton
- Thorntons (U.S. convenience store chain) - James H. Thornton
- THX – Tomlinson Holman
- ThyssenKrupp - Thyssen family and the Krupp family
- Tiffany & Co. – Charles Lewis Tiffany
- Tiffen – Sol Tiffen
- Tim Hortons – Tim Horton
- Timken Company – Henry Timken
- Tokuma Shoten – Yasuyoshi Tokuma
- Toleman – Ted Toleman
- Tom Walkinshaw Racing – Tom Walkinshaw
- Tommy Kaira – Yoshikazu Tomita and Kikuo Kaira
- TOM'S – Nobuhide Tachi and Kiyoshi Oiwa (Tachi Oiwa Motor Sport)
- Toni & Guy – Giuseppe "Toni" and Gaetano "Guy" Mascolo
- Tony Roma's – Tony Roma
- Towers Perrin – John Towers and Charles Perrin
- Toyota Motor – Kiichiro Toyoda
- Toyota Industries – Sakichi Toyoda
- Triple F Racing – Paul, Todd, and Dean Fiore
- Trump Organization – Fred Trump
- Trump Shuttle, Trump Entertainment Resorts, Trump Taj Mahal Casino Resort – Donald Trump
- Tupolev – Andrei Tupolev
- Tupperware Brands – Earl Tupper
- Turner Broadcasting System – Ted Turner
- TVR – TreVoR Wilkinson
- TVS Motors, TVS Electronics – T. V. Sundaram Iyengar
- Tyrrell Racing – Ken Tyrrell
Read more about this topic: List Of Companies Named After People