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.

The World Sportscar Championship was the world series run for sports car racing by the FIA from 1953 to 1992. The championship evolved from a small collection of the most important sportscar, endurance, and road racing events in Europe and North America with dozens of gentleman drivers at the grid to a professional racing series where the world's largest automakers spent millions of dollars per year.