GT4 or GT-Four may refer to:
Automotive SRO GT4, a sports car racing category ADAC GT4 Germany, a German-based sports car championship Dutch GT4 Championship, a Dutch sports car championship GT4 America Series, a North American sports car championship GT4 Australia, an Australian sports car championship GT4 European Series, a European sports car championship Ferrari GT4 Porsche Cayman GT4 Porsche 981 Cayman GT4 Porsche 718 Cayman GT4 Toyota Celica GT-Four
Other uses Gran Turismo 4, a 2004 PlayStation 2 racing video game GT4 (tram), a design of articulated tram which has two bogies and two body sections, and specifically: GT4 (Bremen), a model of GT4 tram used in the German city of Bremen Maschinenfabrik Esslingen GT4, a model of GT4 tram used in Stuttgart and other German cities Denel GT-4, a South African 76mm cannon used on the Rooikat