The 1983 24 Hours of Le Mans was a motor race staged at the Circuit de la Sarthe, Le Mans, France on 18 and 19 June 1983. It was the 51st Grand Prix of Endurance and was also the fourth round of both the 1983 World Endurance Championship and the 1983 European Endurance Championship. The 1983 race was held eight days before the 60th anniversary of the inaugural race held in 1923.

The Porsche 956 was the dominant car in the Championship series, as the company had released cars for customer sale. Although Lancia were quick in practice they were too unreliable in the race. From the start, the works Porsche team took the lead. As rival marques fell away with engine issues, the Porsches consolidated the top-ten. The Kremer car of Mario Andretti led the pursuit, running 2nd for a time on Sunday morning. The Ickx/Bell car had been delayed early in the race, but hard driving had got them back to the top-three. They briefly took the lead soon after dawn but Bell stopped at Mulsanne and lost five laps repairing an electrical fault.

With less than ninety minutes to go, the third works Porsche looked set for victory, after taking the lead in the fifth hour. However, when a door blew off the car Schuppan saw his temperature gauges spike. Al Holbert took the car out for the final stint at a careful pace, with Bell closing in relentlessly, although he was suffering from damaged front brakes. With half an hour to go, Bell unlapped himself to put himself on the lead lap. With two minutes to go, Holbert's engine seized as he passed the pits, having run out of water and overheated. However, by good fortune he was able to get it going again. He made it around one last time, to the finish line, and pulled off straight away. Bell came home just over a minute later running on his reserve fuel-tank. Neither car would likely have done another lap, which would have potentially given the victory to the Kremer Porsche that finished third, six laps back.

The crushing victory by Porsche saw nine of their cars in the top-10, also winning the Index Prize and the win in Group B. The works Mazda had a trouble-free run for a comfortable win in the new Group C Junior class.

This year was the second year of the Group C regulations and there were no changes made. The formula had an open engine capacity, and instead had weight and fuel consumption restrictions. There was a minimum weight of 800 kg put in for safety standards and fuel tanks were a maximum of 100 litres capacity. With no more than 25 fuel stops allowed in the race, it meant a maximum of 2600 litres from the start. With IMSA still using their own sliding weight-scale to balance engine capacity, the major American endurance races, at Daytona and Sebring, could not be part of the World Championship.

This formula attracted great interest from a number of manufacturers and the major privateer teams. However, the prospective costs were prohibitive for smaller teams wanting to compete in the top tier of racing. The FIA governing body took notice of this, and instigated a less expensive division called Group C Junior to encourage those teams. Here the minimum weight was reduced to 700 kg and the fuel-tanks were only 55 litres capacity. With the same 25 fuel stops, this gave those cars a maximum of 1430 litres.

For its part, the Automobile Club de l'Ouest (ACO) made no major changes either. The two 4-hour practice sessions now each included a 1-hour break to allow teams to retrieve stranded cars or make significant repairs or change their car set-ups. With the surge of entries in the new regulations, they could close the lists without needing the MSA classes and the former "grandfathered" classes.

The new regulations had immediately proven successful and this year's Le Mans had an extensive range of entries. It was led by factory teams from Porsche, Lancia and Mazda and over a dozen specialist constructors meant there were 34 cars that could be classed as "works" entries. Porsche dominated the entry list with eleven Group C and eight Group B entries.