Gran Turismo 4 is a 2004 racing simulation video game developed by Polyphony Digital and published by Sony Computer Entertainment for the PlayStation 2. It is the fourth main installment and the sixth overall in the Gran Turismo series. It was released on December 28, 2004, in Japan and Hong Kong, February 22, 2005, in North America, and March 9, 2005, in Europe, and has since been re-issued under Sony's Greatest Hits brand.

The PlayStation 2 (PS2) is a home video game console developed and marketed by Sony Computer Entertainment. It was first released in Japan on 4 March 2000, in North America on 26 October 2000, in Europe on 24 November 2000, and in Australia on 30 November 2000. It is the successor to the PlayStation, as well as the second installment in the PlayStation brand of consoles. As a sixth-generation console, it competed with Nintendo's GameCube, Sega's Dreamcast, and Microsoft's Xbox. It is the best-selling video game console of all time, having sold over 155 million units worldwide, nearly triple the combined sales of the Dreamcast, GameCube, and Xbox.