The 1955 Grand Prix motorcycle racing season was the seventh 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 1 May, with Spanish Grand Prix and ended with Nations Grand Prix in Italy on 4 September.
Points were awarded to the top six finishers in each race. Only the four best races counted in the Sidecars, 125cc and 250cc, while in the 350cc and 500cc championships, the five best results were counted.
Each constructor is awarded the same number of points as their best placed rider in each race.