The 1973 Grand Prix motorcycle racing season was the 25th F.I.M. Road Racing World Championship season.
MV Agusta teammates Phil Read and Giacomo Agostini battled it out for supremacy of the 500cc class but the season was overshadowed by the deaths of Jarno Saarinen and Renzo Pasolini at the Italian round at Monza. The 500cc title runner-up, Kim Newcombe, also died at a non-championship race at Silverstone late in the year. Agostini claimed his 13th championship in the 350cc class. 1973 marked the first year that most of the top competitors joined Agostini in boycotting the Isle of Man TT event over safety concerns.
In the 250cc class, West German Dieter Braun won the crown for Yamaha. Kent Andersson gave Yamaha another title in the 125cc class while Kreidler dominated the 50cc class after the Derbi factory pulled out of racing with Dutchman Jan de Vries taking the crown.
Points were awarded to the top ten finishers in each race. Only the best of five results were counted in the Sidecars championship, while only the best of four results were counted in the in the 50cc championship. The best of seven results were counted in the 125cc championship while only the top six results were counted in the 250cc, 350cc and 500cc championships.
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