The Jaguar XJ (X308) is a full-size luxury saloon car manufactured and marketed by Jaguar Cars for years 1997–2003 across two generations and featuring the Jaguar AJ-V8 engine and Jaguar independent rear suspension. It was the third and final evolution of the Jaguar XJ40 platform that had been in production since 1986. It was preceded by the Jaguar XJ (X300).

Jaguar is the sports car and luxury vehicle brand of Jaguar Land Rover, a British multinational car manufacturer with its headquarters in Whitley, Coventry, England. Jaguar Cars was the company that was responsible for the production of Jaguar cars until its operations were fully merged with those of Land Rover to form Jaguar Land Rover on 1 January 2013.