The Alfa Romeo 158/159, also known as the Alfetta, is a Grand Prix racing car produced by Italian manufacturer Alfa Romeo. It is one of the most successful racing cars ever; the 158 and its derivative, the 159, took 47 wins from 54 Grands Prix entered. It was originally developed for the pre-World War II voiturette formula (1937) and has a 1.5-litre straight-8 supercharged engine. Following World War II, the car was eligible for the new Formula One introduced in 1947. In the hands of drivers such as Nino Farina, Juan Manuel Fangio and Luigi Fagioli, it dominated the first two seasons of the World Championship of Drivers.

Alfa Romeo Automobiles S.p.A. is an Italian luxury car manufacturer and a subsidiary of Stellantis Europe. It was founded on 24 June 1910 in Milan, Italy, as A.L.F.A., an acronym for Anonima Lombarda Fabbrica Automobili. The brand is known for sport-oriented vehicles and has been involved in car racing since 1911. As of 2023 it is a subsidiary of the multinational automotive manufacturing corporation Stellantis.