Ferrari 512 S was a sports prototype car produced by Italian manufacturer Ferrari from late 1969 to 1970. As it name suggests, the car had a 5.0L V12 engine, and was homologated as a Group 4 Sportscar of which a total number of 25 units had to be made. Porsche had already done the same in April 1969 with the Porsche 917, while other Sportscars in the 5-litre class, Ferrari 250 LM, Ford GT40 Mk.I, Lola T70, had been built mainly in 1964, 1965 or 1967.

Several 512S were entered in the 1970 International Championship for Makes by the factory Scuderia Ferrari and private teams. Later that year, modified versions resembling their main competitor, the Porsche 917, were called Ferrari 512 M (for modificata). In the 1971 International Championship for Makes, the factory focused on the new Ferrari 312 PB and abandoned the 512 which was only entered by privateers. From 1972 onwards, the 512 (as the 917) was withdrawn from the world championship following a change in the regulations; some 512s in private hands went on to compete in the Can-Am and Interserie races.

In the mid 1960s, Ferrari had competed in sports prototype racing with the Ferrari P series of 4-litre V12 cars, winning the Le Mans consecutively until 1965. Only very few of the works cars, named 330P4 in 1967, had been handed over to customers teams, often with a simplified engine and named 412P. In 1966 and 1967, the Ford GT40 Mk.II and Mk.IV won Le Mans, using a 7.0-litre engine, and achieving speeds considered too high by the rule makers of FIA/CSI. For 1968, the rules were changed limiting Group 6 prototypes to a maximum engine capacity of 3.0 litres, as in Formula One. Despite having a suitable engine, Ferrari sat out the 1968 season, to return in 1969 with the Ferrari 312 P. For that year, Porsche had taken full advantage of the Group 4 rules, like they already had done in 1966 with making at least 50 Porsche 906 and later 25 Porsche 910, as they were sure they could sell these 2-litre-cars to customers, while Ferrari had failed to built more than 18 of the Dino 206 S which this never earned the S. In late 1968, Porsche made the risky investment of developing and building 25 examples of the 4.5-litre Porsche 917 to allow homologation into the FIA's Group 4 (5 in 1970) sports car category for 1969.

The Sportscar racing world was surprised by the 917. It surely would be a force until 1971, for three seasons. Already being in the process of selling half of his business to Fiat, Enzo Ferrari diverted a part of these funds to match the Porsche investment. While Porsche already delivered 917, additional 512S cars were intended to be sold to racing customers, which meant that several dozen high powered sports cars were available, and with each requiring two drivers in an endurance race, there was a shortage of experienced pilots.

The engine of the 512 S was a completely new 60° V12 with 560 PS (412 kW) output. Compared to Porsche's air-cooled flat-12, it needed a maze of cooling pipes and a heavy radiator. Since the chassis was of steel, reinforced with aluminium sheet, weight was 100 kg more than that of the alloy-framed 917. Notwithstanding the weight difference and higher center of gravity, the Ferrari 512 S and Porsche 917 seemed fairly evenly matched.

At the beginning of 1970 the Ferrari 512s were hampered by predictable early problems, including a weak suspension and transmission problems, but the fact that Porsche already had six months of equally mixed experiences with its 917 in 1969 would be decisive for the rest of the season.

Contrary to Porsche, Ferrari did not organise an intramural competition. At Porsche, JWA Gulf, KG Porsche Salzburg, and later Martini Racing all received direct factory support, in the form of loaned cars. Thus, at least four cars were real works cars, without putting travelling strain on the factory itself, as racing personnel and funds were provided by these professional teams. And even the privateers like AAW Shell Racing and David Piper Racing received much better support than Ferrari's clients. Ferrari did not adopt this modern scheme, but entered cars themselves in the traditional manner, as "Spa Ferrari SEFAC". Having only a few Formula One drivers under contract in the previous years, with the sports car aces since 1966 driving in a fleet of Porsches, Ferrari could barely find qualified drivers for its entries. Besides the factory cars, there were the private cars of Scuderia Filipinetti, NART, Écurie Francorchamps, Scuderia Picchio Rosso, Gelo Racing Team and Escuderia Montjuich. Those private cars never received the same support from the factory. They were considered as field fillers, never as candidates for a win.

Early in the 1970 season, Ferrari won the 1970 12 Hours of Sebring, but the Porsche 917 and the additional Porsche 908/03 at twisty tracks took the remaining nine wins of the championship season. At the 1970 24 Hours of Le Mans, the Ferrari suffered from reliability problems, although it was considered to be equally fast to the 917.^{[citation needed]} Four 512s were entered by Ferrari for that race, but the Vaccarella/Giunti car was out after seven laps, the Merzario/Regazzoni car was out after 38 laps and the Bell/Peterson car was out a lap later, and about five hours later the Ickx/Schetty car was out after 142 laps. For speed tracks such as Le Mans, Spa, Monza and the Österreichring, an extra long rear body panel was fitted on the car.