1981 Grand Prix motorcycle racing season

Mamola started the season strongly with two victories and two second-place finishes to take the lead in the championship but then, Lucchinelli took command with four victories in the next five races to claim the world championship.

[1] Barry Sheene would win the final race of his career with a win in Sweden while a young American named Freddie Spencer made his first foray into the world championships as a member of the Honda factory racing team, riding the four-stroke Honda NR500 up to fifth place at the British Grand Prix before it suffered a mechanical failure.

[1] Germany's Anton Mang scored double world championship victories, defeating defending champion Jon Ekerold for the 350cc title and, winning ten of twelve 250 events to take that title.

[1] Frenchman Michel Rougerie, who finished second in 1975 250 championship, was killed when he was hit by another rider after crashing in the 350 race in Yugoslavia.

[3] The following Grands Prix were scheduled to take place in 1981:[4][5] Points are awarded to the top ten finishers.