The 2015 FIA World Endurance Championship season was the fourth season of the FIA World Endurance Championship auto racing series, co-organized by the Fédération Internationale de l'Automobile (FIA) and the Automobile Club de l'Ouest (ACO). The series was open to Le Mans Prototypes and grand tourer-style racing cars meeting four ACO categories. World championship titles were awarded for Le Mans Prototypes drivers and for manufacturers in the LMP1 category, and several World Endurance Cups and Endurance Trophies were also awarded in all four categories. The season began at the Silverstone Circuit in April and ended at the Bahrain International Circuit in November after eight rounds, and included the 83rd running of the 24 Hours of Le Mans.

The 83rd 24 Hours of Le Mans was a 24-hour automobile endurance event for teams of three drivers each entering Le Mans Prototype and Le Mans Grand Touring Endurance cars held from 10 to 14 June 2015 at the Circuit de la Sarthe, close to Le Mans, France. It was the 83rd running of the 24 Hour race organised by the Automobile Club de l'Ouest as well as the third round of the 2015 FIA World Endurance Championship. A test day was held two weeks prior to the race on 31 May. A record-breaking 263,500 people attended the event.