Following the shortened 1956 calendar, the championship expanded back to seven rounds in 1957. The 24 Hours of Le Mans returned to the schedule after circuit modifications implemented in the aftermath of the 1955 disaster. A new round, the Venezuelan Grand Prix in Caracas, was added for the first time. The RAC Tourist Trophy was again allocated championship status but did not take place, as the Dundrod Circuit — scene of three driver deaths in 1955 — never again hosted championship racing.
Maserati mounted its most ambitious campaign yet, signing Juan Manuel Fangio — then the reigning Formula One World Champion — alongside Stirling Moss, supported by Jean Behra and Harry Schell in the Maserati 450S. Ferrari countered with the 315 S and 335 S, both formidable machines developed from the 290 MM programme.
The opening round at Buenos Aires saw Fangio and Moss lead but retire with transmission failure; a privately entered Ferrari of Temple Buell took victory. At Sebring, Maserati dominated with Fangio and Behra controlling the race, while Ferrari's 315 S entries suffered brake and tyre problems.
The Mille Miglia — still running on open Italian roads despite mounting safety concerns — produced tragedy. Alfonso de Portago and co-driver Edmont Nelson crashed after a tyre failure approximately 10 km from the finish, killing both crew members and nine spectators. Piero Taruffi won the race for Ferrari, but the accident sealed the Mille Miglia's fate: public outrage and criminal proceedings against Enzo Ferrari followed, and the race would not run again in its classic open-road format.
At the Nürburgring, Aston Martin's DBR1/300 — driven by Tony Brooks and Noël Cunningham-Reid — took a surprise victory over both Italian factory teams, the British manufacturer's first championship points of the season. At Le Mans, in an equally significant upset, privately entered Jaguar D-types run by the Scottish entrant Ecurie Ecosse swept the top four and sixth positions, defeating the works Ferrari and Maserati teams. It was the first time a single nation had so completely dominated Le Mans.
Ferrari and Maserati returned to the front at the Swedish round, where Moss and Behra shared victory. Heading into the Venezuelan finale, Maserati needed maximum points and sent a full team of four cars, including the powerful 450S.
The Venezuelan Grand Prix at Caracas became one of the most costly races in Maserati's history. On the second lap, Masten Gregory rolled Buell's 450S. Moss then collided with a backmarker, demolishing his car. A third 450S caught fire during a pit stop, injuring Behra, though he and Schell continued until Joakim Bonnier's car struck Schell following a wheel loss. All four Maserati entries were eliminated before the finish. Ferrari took a 1-2 result and the championship.
The financial consequences for Maserati proved terminal for their works racing programme. The cost of destroying four expensive 450S cars in a single race pushed the company into severe financial difficulty at the very moment Fangio was delivering their first Formula One World Championship. Maserati withdrew from all factory racing at the end of 1957, spending decades rebuilding as a road car manufacturer.
Ferrari won the 1957 World Sportscar Championship manufacturers' title. Maserati finished second despite having arguably the faster cars and drivers for much of the season. Aston Martin and Jaguar — the latter through private entries — demonstrated that British manufacturers could now compete at the highest level.
The 1957 season stands as one of the most eventful in endurance racing history. The de Portago accident at the Mille Miglia effectively ended open-road racing in Italy at the championship level. Maserati's Venezuelan collapse removed one of the sport's great works teams from competition for a generation. Simultaneously, the Le Mans result confirmed that independent British teams could defeat the Italian factory establishments, presaging the Aston Martin victories to come. The 1957 championship also marked the last season before new regulations would reshape the technical landscape of sports car racing from 1958 onward.