The 1955 Florida International Twelve Hour Grand Prix of Endurance took place on 13 March, on the Sebring International Raceway (Florida, United States). It was the second round of the F.I.A. World Sports Car Championship. For the fifth running of the event, the 5.2 mile course had been widened and smoothed with a new asphalt topping laid down. This was for safety and would allow the cars to achieve greater speed, especially in some of the corners.