List of 50/80cc World Riders' Champions

Grand Prix motorcycle racing is the premier championship of motorcycle road racing, which has been divided into three classes since 1990: 125cc, 250cc and MotoGP. Classes that have been discontinued include 350cc, 50cc/80cc and sidecar. The 50/80cc referred to the size of the engines of the motorcycles that raced in that class. The Grand Prix Road Racing World Championship was established in 1949 by the sport's governing body, the Fédération Internationale de Motocyclisme (FIM), and is the oldest motorsport World Championship. The 50cc was introduced in 1962, 13 years after the start of the first world championships. The category was replaced by 80cc in 1984 and the class was subsequently discontinued in 1989.

Each season consisted of five to ten Grands Prix contested on closed circuits, as opposed to public roads. Points earned in these events counted toward the drivers' and constructors' World Championships. The driver's and constructor's championship were separate championships, but were based on the same point system. The points systems used in the championship varied over the years. The first championship in 1962 awarded points from first to sixth place; a point was also awarded for the rider who completed the fastest lap. The last championship in 1989 awarded points from first to fifteenth place. Results from all Grands Prix counted towards the championships; however, in some seasons only a certain number of results were counted.

Ángel Nieto won the most championships during his career with six. Stefan Dörflinger won the second most championships with four, and Hans-Georg Anscheidt and Jorge Martínez won the third most with three. Spanish riders won the most championships; four riders won a total of 12 championships. Swiss and German riders were second with four, while Ernst Degner won the inaugural championship in 1962. Manuel Herreros was the last champion before the class was discontinued in 1989.

Champions

 * The "Season" column refers to the season the competition was held, and wikilinks to the article about that season.
 * The "Margin" column refers to the margin of points by which the winner defeated the runner-up.