1981 Grand Prix motorcycle racing season
The 1981 Grand Prix motorcycle racing season was the 33rd F.I.M. Road Racing World Championship season.
Season summary
riders Marco Lucchinelli and Randy Mamola battled it out to the final race of the season with the Italian rider claiming the crown and Mamola finishing runner-up for the second consecutive year. 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 GP world, riding the four-stroke Honda NR500 up to fifth place at the British Grand Prix before it broke down.Germany's Anton Mang scored double world championships, defeating defending champion Jon Ekerold for the 350cc title and winning ten of twelve 250 events to take that title. 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. Angel Nieto won his tenth championship by winning eight of twelve rounds on his Minarelli while Ricardo Tormo won the 50cc crown for Bultaco.
Beginning in 1981, motorcycle frame technology evolved quickly as motorcycle manufacturers moved from the steel, featherbed frame chassis first developed in the 1950s, to aluminium frames featuring large, twin beams as first pioneered by Spanish constructor, Antonio Cobas.
1981 Grand Prix season calendar
The following Grands Prix were scheduled to take place in 1981:| Round | Date | Grand Prix | Circuit |
| 1 | 22 March |  Argentine Grand Prix | Autódromo Municipal de la Ciudad de Buenos Aires |
| 2 | 26 April |  Großer Preis von Österreich | Salzburgring |
| 3 | 3 May |  Großer Preis von Deutschland | Hockenheimring |
| 4 | 10 May |  Gran Premio delle Nazioni | Autodromo Nazionale Monza |
| 5 | 17 May |  Grand Prix de France Moto | Circuit Paul Ricard |
| 6 | 24 May |  Gran Premio de España | Circuito Permanente Del Jarama |
| 7 | 31 May |  Yu Grand Prix | Automotodrom Rijeka |
| 8 | 27 June |  Dutch TT Assen | TT Circuit Assen |
| 9 | 5 July |  Grand Prix Moto | Circuit de Spa-Francorchamps |
| 10 | 12 July |  Gran Premio di San Marino | Autodromo Dino Ferrari |
| 11 | 2 August |  Marlboro British Grand Prix | Silverstone Circuit |
| 12 | 9 August |  Finnish GP | Imatra Circuit |
| 13 | 16 August |  Swedish TT | Scandinavian Raceway |
| 14 | 30 August |  Grand Prix ČSSR | Brno Circuit |
Calendar changes
- The Argentine Grand Prix was added to the calendar.
- The Austrian Grand Prix returned on the calendar after a one-year absence. Last year's scheduled running of the event was cancelled due to snowy weather conditions on race week.
- The German Grand Prix was moved forward, from 24 August to 3 May.
- The German Grand Prix moved from the Nürburgring-Nordschleife to the Hockenheimring for the next three years due to ongoing construction to replace it with a new venue.
- The Nations Grand Prix moved from the Circuito Internazionale Santa Monica to the Autodromo Nazionale Monza.
- The Yugoslavian Grand Prix was moved forward, from 15 June to 31 May.
- The Belgian Grand Prix moved from Circuit Zolder to Circuit de Spa-Francorchamps after the track problems at Spa-Francorchamps were resolved.
- The San Marino Grand Prix was added to the calendar.
- The Finnish Grand Prix was moved back, from 27 July to 9 August.
- The Swedish Grand Prix was added to the calendar after a one-year absence.
Results and standings
1981 Grand Prix season results
500cc riders' standings
;Scoring systemPoints are awarded to the top ten finishers. A rider has to finish the race to earn points.
| Position | 1st | 2nd | 3rd | 4th | 5th | 6th | 7th | 8th | 9th | 10th |
| Points | 15 | 12 | 10 | 8 | 6 | 5 | 4 | 3 | 2 | 1 |
350cc standings250cc standings125cc standings50cc standings |