The 1955 Formula One season was the ninth season of FIA Formula One motor racing. It featured the 1955 World Championship of Drivers, which commenced on 16 January 1955 and ended on 11 September after seven races. Juan Manuel Fangio won his second consecutive World Championship title in a season curtailed by tragedies.

Formula One, commonly known as Formula 1 or F1, is the highest class of international racing for open-wheel single-seater formula racing cars sanctioned by the Fédération Internationale de l'Automobile (FIA). The FIA Formula One World Championship has been one of the world's premier forms of racing since its inaugural running in 1950. The word formula in the name refers to the set of rules all participants' cars must follow. A Formula One season consists of a series of races, known as Grands Prix. Grands Prix take place in multiple countries and continents on either purpose-built circuits or closed public roads.