The 2021 FIA Formula 2 Championship was a motor racing championship for Formula 2 cars that was sanctioned by the Fédération Internationale de l'Automobile (FIA). The championship was the fifty-fifth season of Formula 2 racing and the fifth season run under the FIA Formula 2 Championship moniker. It was an open-wheel racing category that served as the second tier of formula racing in the FIA Global Pathway. The category was run in support of selected rounds of the 2021 FIA Formula One World Championship. As the championship was a spec series, all teams and drivers competing in the championship ran the same car, the Dallara F2 2018. The championship was contested over twenty-four races at eight circuits. It began in March 2021 with a round in support of the Bahrain Grand Prix, and ended in December where it supported the Abu Dhabi Grand Prix.

Formula Two is a type of open-wheel formula racing category first codified in 1948. It was replaced in 1985 by Formula 3000, but revived by the FIA from 2009–2012 in the form of the FIA Formula Two Championship. The name returned again in 2017 when the former GP2 Series became known as the FIA Formula 2 Championship.