Alain Marie Pascal Prost (French pronunciation: [alɛ̃ pʁɔst]; born 24 February 1955) is a French former racing driver and motorsport executive, who competed in Formula One from 1980 to 1993. Nicknamed "the Professor", Prost won four Formula One World Drivers' Championship titles and—at the time of his retirement—held the records for most wins (51), fastest laps (41), and podium finishes (106).

Born in Lorette, Loire, Prost began karting aged 14, winning the junior direct-drive Karting World Cup four years later, and progressing to junior formulae in 1976. Prost won his first title at the Formula Renault National Championship that year, prior to winning the Challenge de Formule Renault Europe in 1977. Replaced by the French Formula Three Championship the following season, he successfully defended his titles in 1978 and 1979. His junior career culminated in his victory at the 1979 FIA European Formula 3 Championship with Oreca. Prost signed for McLaren in 1980, making his Formula One debut at the Argentine Grand Prix, where he finished sixth. He moved to Renault in 1981, taking his maiden victory at his home Grand Prix in France, with further wins in the Netherlands and Italy. Following multiple race wins in his 1982 campaign with Renault, Prost finished runner-up to Nelson Piquet in the 1983 World Drivers' Championship after retiring with a turbo failure in the title-decider. Prost was sacked by Renault two days later for his post-season comments and moved back to McLaren for 1984, where he finished runner-up to teammate Niki Lauda by a record half-point.

In 1985, Prost won his maiden title with McLaren, becoming the first World Drivers' Champion from France. He successfully defended his title the following season, amidst a close title battle with Piquet and Nigel Mansell. After winning several races in his 1987 campaign, Prost was partnered by Ayrton Senna. Together, they won all Grands Prix bar one in 1988—driving the Honda-powered MP4/4—with Senna taking the title by three points. Their fierce rivalry culminated in title-deciding collisions at Suzuka in 1989 and 1990, despite Prost's move to Ferrari in the latter, with Prost winning the former championship and Senna taking the following. Amidst a winless 1991 campaign, he was sacked by Ferrari over comments made about the 643. After a year hiatus, Prost returned with Williams in 1993, breaking several records on the way to his fourth championship and retiring at the end of the season. He returned to Formula One as the owner of Prost Grand Prix from 1997 to 2001, having purchased Ligier. Prost held an advisory role at Renault—later re-branded as Alpine—from 2017 to 2021.

After retiring from Formula One, Prost was a race-winner in the 2005 FFSA GT Championship, and entered the Race of Champions in 2010, representing France alongside Sébastien Loeb. In ice racing, Prost is a three-time champion of the Andros Trophy, competing from 2003 to 2012. He was the co-owner of Renault e.dams in Formula E until 2018, winning three consecutive Teams' Championships from 2014–15 to 2016–17. Prost was inducted into the International Motorsports Hall of Fame in 1999.

Alain Prost was born in the commune of Lorette near the town of Saint-Chamond, in the département of Loire close to Saint-Étienne, France to André Prost and Marie-Rose Karatchian, born in France of Armenian descent. His father ran a furniture store. Prost had one older brother called Daniel, who died of cancer in September 1986. Prost was an active and athletic child, who enthusiastically took part in diverse sports, including wrestling, roller skating and football. In doing so he broke his nose several times. He considered careers as a gym instructor or a professional footballer before he discovered kart racing at the age of 14 while on a family holiday. This new sport quickly became his career of choice. At age 16, he bought his first kart with money he saved working for his father's shop.

Prost won several karting championships in his teens. In 1974, he became a full-time racer. He won the French senior karting championship in 1975.

Prost made the transition to open-wheel racing in 1976 and rapidly progressed through the junior categories. That year, he dominated French Formula Renault, winning the title and all but one race. In 1977, he won the Formula Renault European championship. In 1978, he won the French Formula Three championship while simultaneously competing in the European Formula Three category. Finally, in 1979, he won both the European and French Formula Three titles. He also made three guest appearances in European Formula Two in 1977 and 1978.

Prost's Formula Three wins drew interest from Formula One teams and sponsors. Before the final race of the 1979 season, Paddy McNally and John Hogan of Marlboro (McLaren's lead sponsor) offered to cover the costs of a third McLaren car so that Prost could make an early Formula One debut, but Prost declined the cameo appearance, reasoning that it would be a mistake to debut in Formula One without being fully prepared: "I didn't know Watkins Glen and I didn't know the car. I said I thought it would be a better idea to organise a test."