1973 FIM Motocross World Championship

The 1973 FIM Motocross World Championship was the 17th edition of the Motocross World Championship organized by the FIM and reserved for 500cc and 250cc motorcycles.

The FIM implements new motorcycle minimum weight restrictions as well as a new championship points scoring formula for the 1973 season. Previously, the FIM had awarded points at each Grand Prix based on a competitor's overall position after two heat races. This meant that a racer could win the first heat race yet still finish with reduced or zero points, depending on their performance in the second heat race. Beginning in 1973, points would be awarded heat race by heat race. The Grand Prix races are still run with two heat races, but it is the sum of the results of each heat that counts for the final classification of the World Championship and not the points acquired at each Grand Prix.

The 1973 season also marked the beginning of the single shock absorber rear suspension era in motocross racing when Yamaha introduced their revolutionary new Monoshock suspension. The new suspension system doubled the suspension travel available from previous systems. By the end of the decade, all the major motorcycle manufacturers would produce motorcycles using their own versions of the single shock absorber rear suspension.