The third generation of the XJ saloon carried the internal designations X350, X356 and X358 to give the car its internal designations, with the X350 being the initial offering and the subsequent numbers referring to the two facelifts the model receive during its life cycle.

Jaguar XJ (1968–1973) “XJ” is originally a code name that stands for “eXperimental Jaguar.” The development team starts with an idea for a four-seat GT car to replace the E-type but later zeroes in on a more conventional four-door to replace Jaguar's three sedans with one.

The model was discontinued in 2019.

Both the X350 and X358 were available with a six-speed automatic transmission, a range of petrol and diesel engines (V6, V8, and supercharged V8), numerous trim levels, and short wheelbase (2003–2009) or long wheelbase (2005–2009) car body configurations.