Mario Gabriele Andretti (born February 28, 1940) is an American former racing driver and businessman, who competed in Formula One from 1968 to 1982, and IndyCar from 1964 to 1994. Andretti won the Formula One World Drivers' Championship in 1978 with Lotus, and won 12 Grands Prix across 14 seasons. In American open-wheel racing, Andretti won four IndyCar National Championship titles and the Indianapolis 500 in 1969; in stock car racing, he won the Daytona 500 in 1967. In endurance racing, Andretti is a three-time winner of the 12 Hours of Sebring.

Born in the Kingdom of Italy, Andretti's family emigrated to the United States when he was 15 during the Istrian–Dalmatian exodus. Andretti won the Formula One World Championship in 1978, four IndyCar titles, including three under USAC sanctioning, and one in CART. He is the only driver to win the Indianapolis 500 (1969), Daytona 500 (1967) and the Formula One World Championship, and, along with Juan Pablo Montoya, the only driver to have won a race in the NASCAR Cup Series, Formula One, and an Indianapolis 500. As of 2023, Andretti's victory at the 1978 Dutch Grand Prix is the most recent Formula One win by an American driver. Andretti had 109 career wins on major circuits. Andretti is one of only three drivers to have won races in Formula One, IndyCar, the World Sportscar Championship, and NASCAR. He has also won races in midget car racing and sprint car racing.

Andretti is the only person to be named United States Driver of the Year in three decades (1967, 1978, and 1984). He was also one of only three drivers to have won major races on road courses, paved ovals, and dirt tracks in one season, a feat that he accomplished four times. With his final IndyCar win in April 1993, Andretti became the first driver to have won IndyCar races in four different decades and the first to win automobile races of any kind in five.

In American popular culture, Andretti's name has become synonymous with speed, similar to Barney Oldfield in the early 20th century, as well as Michael Schumacher and Lewis Hamilton in Europe. Andretti is set to serve on the board of directors of Cadillac in Formula One from its debut 2026 season onwards.