TCT is a three-letter abbreviation which may refer to:
- Teenage Cancer Trust
- Texas City Terminal Railway
- The Coroner's Toolkit, computer forensic software
- The Catholic Transcript, a Hartford, CT catholic paper.
- Thrombin clotting time, a test used in blood coagulation.
- Tocotrienol, a group of four isomers occurring in Vitamin E
- Touring Club de Tunisie, a member of the FIA
- Trans Canada Trail, A proposed 18,000km trail that would stretch across Canada
- Tri-State Christian Television, a 24-hour Christian cable television network broadcasting to 15 U.S. States and Canada. (Was formerly known as Total Christian Television)
- Tungsten carbide-tipped, a descriptor for blades, saws, and the like hardened with a tungsten carbide compound
- Tilted Component Telescope, an optical instrument
- Torrance Tests of Creative Thinking (TTCT)