The 1981 FIA Formula One World Championship was the 35th season of FIA Formula One motor racing. It featured the 1981 Formula One World Championship for Drivers and the 1981 Formula One World Championship for Manufacturers, which were contested over a fifteen-race series that commenced on 15 March and ended on 17 October. The 1981 South African Grand Prix, as a non-championship race due to difficulties from the ongoing FISA–FOCA war, was open to Formula One entrants but was not part of the World Championship.

The FISA–FOCA war was a political battle contested throughout the early 1980s by two now-defunct representative organizations in Formula One motor racing, the Fédération Internationale du Sport Automobile (FISA) and the Formula One Constructors Association (FOCA). The battle boiled during the late 1970s and early 1980s and came to a head when the racing teams affiliated with FOCA, an equivalent to a racing team union, boycotted the 1982 San Marino Grand Prix.