After five historic victories, three in succession, between 1951 and 1957, Jaguar was to wait 31 years for another podium finish in the 24 Hours of Le Mans. Its 1988 success came after a long period that began with the XJR5 in the early 1980s and culminated in the development of the first Group C, the XJR6, which evolved into the XJR8 and finally the victorious XJR9. With this car, they hoped to repeat their success of 1989, but were forced by the powerful Sauber-Mercedes C9 to improve further. Next came the new XJR10 and XJR11 with supercharged 3 and 3.5-litre engines, competing respectively in the IMSA championships in America and the Sport-Prototypes in Europe, but their V6s were too fragile for the marathons of Daytona and Le Mans, where the good old V12 derived from a 7-litre engine remained the best option.

For 1990, the XJR12 was based on the XJR9; two of the new cars were built on chassis from the previous series, including the one that was to win. The modifications did not alter the architecture of the car, which retained its basic dimensions, wheelbase, carbon structure and mechanicals, but its aerodynamics were refined to adapt it to the specific characteristics of the tracks in the two configurations, one of which was specific to the new Le Mans circuit. From the 1990 edition onwards, the FIA required the ACO to 'cut' the Hunaudières' very long straight with two chicanes in order to reduce the maximum speed and avoid a repeat of the serious accidents of previous years. These changes to the track gave Jaguar the advantage of eliminating its main rivals indirectly.

As a result, Sauber-Mercedes decided not to take part when the FIA excluded the Le Mans 24 Hours from the calendar of events qualifying for the World Sports Car Championship until the work on adapting the circuit had been completed.