The Jaguar Mark X, later renamed the Jaguar 420G, was British manufacturer Jaguar's top-of-the-range saloon car for a decade, from 1961 to 1970. The large, luxurious Mark X not only succeeded the Mark IX as the company's top saloon model, but radically broke with both its predecessor's styling and technology.

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.