Italian motor manufacturer Alfa Romeo has participated multiple times in Formula One. The brand has competed in motor racing as both a constructor and engine supplier sporadically between 1950 and 1987, and later as a commercial partner between 2015 and 2023. The company's works drivers won the first two World Drivers' Championships in the pre-war Alfetta: Nino Farina in 1950 and Juan Manuel Fangio in 1951. Following these successes, Alfa Romeo withdrew from Formula One.

During the 1960s, although the company had no official presence in the top tier of motorsport, several Formula One teams used independently developed Alfa Romeo engines to power their cars. In the early 1970s, Alfa provided Formula One support for their works driver Andrea de Adamich, supplying adapted versions of their 3-litre V8 engine from the Alfa Romeo Tipo 33/3 sports car to power Adamich's McLaren (1970) and March (1971) entries. None of these engine combinations scored championship points.

In the mid-1970s, Alfa engineer Carlo Chiti designed a flat-12 engine to replace the T33 V8, which achieved some success in taking the 1975 World Sportscar Championship. Bernie Ecclestone, then owner of the Brabham Formula One team, persuaded Alfa Romeo to supply this engine free for the 1976 Formula One season. Although the Brabham-Alfa Romeo's first season was relatively modest, during the 1977 and 1978 World Championships their cars took 14 podium finishes, including two race victories for Niki Lauda.

The company's sporting department, Autodelta, returned as the works team in 1979. This second period as a constructor was less successful than the first. Between the company's return and its withdrawal as a constructor at the end of 1985, Alfa works drivers did not win a race and the team never finished higher than sixth in the World Constructors' Championship. The team's engines were also supplied to Osella from 1983 to 1987, but they scored only two World Championship points during this period.

The Alfa Romeo logo returned to Formula One in 2015, appearing on the Scuderia Ferrari cars. Alfa Romeo became the title sponsor for the Ferrari-powered Sauber team from 2018, and this commercial partnership was increased to a full renaming of the team beginning in 2019. Alfa Romeo did not have any technical involvement with the team, and the company ended its sponsorship of Sauber after 2023 and left Formula One to allow the team to be taken over by Audi from 2026.

Before World War II, Alfa Romeo was a dominant presence in Grand Prix motor racing. The P2 and the P3 consistently achieved victories until 1934, when the German Mercedes and Auto Union cars emerged and posed serious competition. By this time, Alfa Romeo had withdrawn temporarily as a manufacturer and was run by Enzo Ferrari and his Scuderia Ferrari team from 1929 to 1938. From 1934 to the start of World War II in 1939, Alfa often experienced a scarcity of victories, as their cars appeared underdeveloped compared to the technically advanced Mercedes.

After Alfa Corse retrieved its control of the brand from Ferrari, they made the Alfa Romeo 158 for the 1938 season. The 158, after subsequent updates, went on to become a dominant force in Gran Prix racing in the aftermath of the war. Alfa continued to use this car at Grands Prix from 1946 to 1948, withdrawing from racing in 1949 due to death of Jean-Pierre Wimille, Achille Varzi, and Carlo Felice Trossi, dominating the 1947 and 1948 Grand Prix seasons.

Alfa Romeo experienced astounding success in the first two seasons of the Formula One World Championship. In 1950, Giuseppe Farina won the inaugural World Drivers' Championship in a 158 with a supercharger. The success was replicated the following year by Juan Manuel Fangio while driving an Alfetta 159 (an evolution of the 158 with a two-stage compressor). The Alfetta's engines were extremely powerful for their capacity: in 1951 the 159 engine was producing around 420 bhp (310 kW) but this was at the price of fuel consumption of 125 to 175 litres per 100 km (1.5 mpg–U.S. / 3 mpg–imp).