IMSA (International Motor Sports Association) is a North American sports car racing sanctioning body based in Daytona Beach, Florida. The IMSA WeatherTech SportsCar Championship is a sports car racing series based in the United States and Canada and organized by IMSA. It is a result of a merger between two existing North American sports car racing series, the American Le Mans Series and Rolex Sports Car Series. The premier multiclass racing organization in North America is the International Motor Sports Association (IMSA) .

IMSA WeatherTech SportsCar Championship features five classes: GTP, LMP2, LMP3, GTD Pro, and GTD. The GTP class is the fastest and most technologically advanced class, featuring the most expensive and exotic cars. LMP2 and LMP3 are prototype classes, with LMP2 being the faster of the two. GTD Pro and GTD are GT (Grand Touring) classes, with GTD Pro being the faster of the two.

The cars are lined up based on qualifying results, with the fastest overall car starting from the pole position, the second fastest qualifier starting second, and continuing until the grid is complete. Qualifying is divided into a 20-minute segment for GTP and 15-minute segments for all other IMSA WeatherTech SportsCar Championship classes. The driver with the fastest lap in each class earns the Motul Pole Award.

IMSA races are held on road courses, and the series features some of the most iconic tracks in North America, such as Daytona International Speedway, Sebring International Raceway, and Road America. The season begins with its premier race, the Rolex 24 at Daytona, the last weekend of January and ends with the Petit Le Mans, another North American Endurance Cup race, in early October.

IMSA is unique in that despite there being five races going on at once, they are all out on track sharing the same track at the same time. The only time that these classes are separated is during pit stops.

In summary, IMSA is a North American sports car racing sanctioning body that organizes the IMSA WeatherTech SportsCar Championship, a sports car racing series featuring five classes of cars that race on road courses across the United States and Canada.