The 2021 Super GT Series was a motor racing championship based in Japan for grand touring cars. The series is sanctioned by the Japan Automobile Federation (JAF) and run by the GT Association (GTA). It was the twenty-ninth season of the Japan Automobile Federation Super GT Championship which includes the All Japan Grand Touring Car Championship (JGTC) era, and the seventeenth season under the Super GT name. It was the thirty-ninth overall season of a national JAF sportscar championship, dating back to the All Japan Sports Prototype Championship.