GT1 may refer to FIA GT1 World Championship Gran Turismo (1997 video game) Group GT1, a top-line category in GT racing 1993–1998 (known as "GTS" between 2000–2004), revived 2005-2011 Toyota GT-One, competed in the above category Porsche 911 GT1, competed in the above category GT-1 (missile), a World War II glide torpedo Gemini 1 (Gemini-Titan 1, or GT-1), an uncrewed Project Gemini mission Tweed GT-1, glider Denel GT-1, a South African cannon