Grand Prix motorcycle racing is the premier championship of motorcycle road racing, which has been divided into three classes since 1997: 125cc, 250cc and MotoGP. Former classes that have been discontinued include 350cc, 50cc/80cc and Sidecar. The premier class is MotoGP, which was formerly known as the 500cc 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 in existence. The motorcycles used in MotoGP are purpose built for the sport, and are unavailable for purchase by the general public because they cannot be legally ridden on public roads. From the mid-1970s to 2002, the top class of GP racing allowed 500cc with a maximum of four cylinders, regardless of whether the engine was a two-stroke or four-stroke. Rule changes were introduced in 2002, to facilitate the phasing out of two-stroke engines.
Each season consists of 12 to 18 Grands Prix contested on closed circuits, as opposed to public roads. Points earned in these events count toward the riders' and constructors' world championships. The riders' and constructors' championship are separate championships, but are based on the same point system. The number of points awarded at the end of each race to the top 15 qualifying riders depends on their placement. Points received by each finisher, from first place to 15th place: 25, 20, 16, 13, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1. Historically, there have been several points systems. Results from all current Grands Prix count towards the championships; in the past, only a certain number of results were counted.
Giacomo Agostini has won the most championships, with eight, including a record seven championships in succession from 1966 to 1972. Marc Márquez is the youngest to win the championship; he was 20 years and 266 days old when he won the championship in 2013. Italian riders have won the most championships; six riders have won a total of twenty championships. Riders from Great Britain have won the second most; six riders have won a total of seventeen championships. Riders from the United States have won the third most, as seven riders have won a total of fifteen championships. Leslie Graham won the inaugural championship in 1949.
|Champion also won 350cc Championship in that season|
|*||Champion also won 250cc Championship in that season|
|—||Indicates information is not available|
- 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.
|Giacomo Agostini||8||1966, 1967, 1968, 1969, 1970, 1971, 1972, 1975|
|Valentino Rossi||7||2001, 2002, 2003, 2004, 2005, 2008, 2009|
|Mick Doohan||5||1994, 1995, 1996, 1997, 1998|
|Marc Márquez||2013, 2014, 2016, 2017, 2018|
|Geoff Duke||4||1951, 1953, 1954, 1955|
|John Surtees||1956, 1958, 1959, 1960|
|Mike Hailwood||1962, 1963, 1964, 1965|
|Eddie Lawson||1984, 1986, 1988, 1989|
|Kenny Roberts||3||1978, 1979, 1980|
|Wayne Rainey||1990, 1991, 1992|
|Jorge Lorenzo||2010, 2012, 2015|
|Umberto Masetti||2||1950, 1952|
|Phil Read||1973, 1974|
|Barry Sheene||1976, 1977|
|Freddie Spencer||1983, 1985|
|Casey Stoner||2007, 2011|
- Bold indicates active rider.
|Rhodesia and Nyasaland||1||1|
- "Winners". MotoGP. Retrieved 7 May 2011.
- Marshall 1997, p. 289
- "Basics". MotoGP. Retrieved 3 February 2012.
- "Bikes". MotoGP. Retrieved 3 February 2012.
- "FIM Road Racing World Championship Grand Prix Regulations 2009" (PDF). Fédération Internationale de Motocyclisme. 31 January 2009. p. 44. Archived from the original (PDF) on 10 March 2012. Retrieved 2 September 2009.
- "Key Rules". MotoGP. Retrieved 3 February 2012.
- "Freddie Spencer". AMA Motorcycle Hall of Fame. Retrieved 9 January 2012.
- "America's winning heritage in MotoGP". MotoGP. Retrieved 11 December 2008.