Janet Guthrie (born March 7, 1938, in Iowa City, Iowa) is a retired professional race car driver and the first woman to qualify and compete in both the Indianapolis 500 and the Daytona 500.

Guthrie was originally an aerospace engineer and after graduating from the University of Michigan, she worked with Republic Aviation. She began racing in 1963 on the SCCA circuit in a Jaguar XK 140 and by 1972, she was racing on a full-time basis.

In the 1976 World 600, Guthrie finished 15th, becoming the first woman to compete in a NASCAR Winston Cup superspeedway race. Guthrie would go on to compete in four more races that season. The following season, she competed in her first Daytona 500, finishing 12th when her car's engine blew two cylinders with ten laps to go. For the race, though, she still earned the honor of Top Rookie. Overall, Guthrie went on to compete in 33 races in NASCAR over four seasons. Her highest finish, sixth place at Bristol in 1977, is the best finish by a woman in a top-tier NASCAR race, now currently tied with Danica Patrick in 2014.

Guthrie qualified for and competed in the 1977 Indianapolis 500, but finished 29th with engine troubles. She would compete in two more Indy 500s, finishing as high as ninth in the 1978 race. Overall, she competed in 11 IndyCar events finishing as high as fifth. During her unsuccessful bid to qualify for the 1976 race, many of the drivers in the male dominated sport stated that the only reason she did not qualify was mainly due to her gender. These comments angered then three-time champion A.J. Foyt to the point he had Guthrie perform a four lap timed practice around the Indianapolis track using his back up car. Had she been qualifying, she would've done so in ninth. This prompted Foyt to state that the only reason Guthrie did not qualify was due to the lack of funds for her team, and not because of her gender.

Nevertheless, Guthrie's place in history was secure. In 1979, the Supersisters trading card set was produced and distributed; one of the cards featured Guthrie's name and picture. Her helmet and race suit can be found in the Smithsonian Institution and Guthrie was one of the first elected to the International Women's Sports Hall of Fame. She was inducted into the International Motorsports Hall of Fame on April 27, 2006. Her 2005 autobiography, Janet Guthrie: A Life at Full Throttle, has received critical praise in such publications as Sports Illustrated.