GT3

• Porsche 911 GT3, a high performance version of the Porsche 911
• IMSA GT3 Cup Challenge, a one-make racing series featuring the Porsche 911 GT3
• IMSA GT3 Cup Challenge Canada, the Canadian subsidiary series
• Group GT3, a class of auto racing
• FIA GT3 European Championship, a defunct series based on Group GT3
• GT3 (1998–1999), a former class of auto racing for grand touring cars, used by IMSA and the SCCA

• Gran Turismo 3: A-Spec, a 2001 car racing game developed for the PlayStation 2
• British Rail GT3, a prototype gas turbine locomotive

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