The International Motor Sports Association (IMSA) is a North American sports car racing sanctioning body based in Daytona Beach, Florida, under the jurisdiction of the ACCUS arm of the FIA. It was started by John Bishop, a former executive director of SCCA, and his wife Peggy in 1969 with help from Bill France Sr. of NASCAR. Beginning in 2014, IMSA is the sanctioning body of the WeatherTech SportsCar Championship, the premier series resulting from the merger of Grand-Am Road Racing and the American Le Mans Series. IMSA is owned by NASCAR, as a division of the company.

Sports car racing is a form of motorsport road racing which utilises sports cars that have two seats and enclosed wheels. They may be purpose-built prototypes or grand tourers based on road-going models. Sports car racing is one of the main types of circuit auto racing, alongside open-wheel racing, touring car racing and stock car racing. Sports car races are often, though not always, endurance races that are run over particularly long distances or large amounts of time, resulting in a larger emphasis on the reliability and efficiency of the car and its drivers as opposed to outright car performance or driver skills. The FIA World Endurance Championship is an example of one of the best known sports car racing series.