1951 Grand Prix motorcycle racing season

Geoff Duke, the 1951 350cc and 500cc World Champion.

The 1951 Grand Prix motorcycle racing season was the third F.I.M. Road Racing World Championship Grand Prix season. The season consisted of eight Grand Prix races in five classes: 500cc, 350cc, 250cc, 125cc and Sidecars 500cc. It began on 8 April, with Spanish Grand Prix and ended with Nations Grand Prix on 9 September. As of 2024, this is the most recent season the premier class was won by a non-Japanese or non-Italian constructor.