Jaguar's independent rear suspension (IRS) unit has been a common component of a number of Jaguar production cars since 1961, passing through two major changes of configuration up to 2006 and last used in the Jaguar XK8 and Aston Martin DB7. This article concentrates on the first generation Jaguar IRS, which firmly established the marque's reputation for suspension sophistication, combining as it did smooth ride with excellent roadholding and low levels of noise, vibration, and harshness (NVH). The two generations overlap in time due to their being used in both full size and sports models that were updated at different times.

The Jaguar XJ (XJ40) is a full-size luxury saloon manufactured by Jaguar Cars between 1986 and 1994. It was officially unveiled on 8 October 1986 as an all-new, second generation of the XJ to replace the Series III, although the two model ranges were sold concurrently until the Series III was discontinued in 1992. The XJ40 used the Jaguar independent rear suspension arrangement, and featured a number of technological enhancements, such as electronic instrument cluster.