Grand Theft Auto IV (abbreviated to GTA IV) is a sandbox-style action-adventure video game developed by Rockstar North. It is the ninth title in the Grand Theft Auto series and the first in its fourth generation. Grand Theft Auto IV was released worldwide (except in Japan) on 29 April 2008 for both PlayStation 3 and Xbox 360. Two episodic packs will be released exclusively for the Xbox 360, the first of which has been delayed until the first quarter of Take-Two’s 2009 financial year.

The game is set in a redesigned rendition of Liberty City, a fictional city based heavily on modern day New York City. It follows Niko Bellic, a war veteran from Eastern Europe, who comes to the United States in search of the American Dream, only to find his cousin has lied about the wealth that was promised to be awaiting him. Like other games in the series, GTA IV features "open-world" gameplay that gives the player more control over their playing experience. GTA IV is the first console game in the series to feature an online multiplayer mode, which contains fifteen different game types.

A major commercial and critical success, Grand Theft Auto IV broke sales records by selling about 3.6 million units on its first day of release and grossing more than $500 million in its first week. The game received overwhelmingly positive reviews, becoming the highest-rated video game of all-time on review aggregator sites Metacritic and Game Rankings for over a month after it was launched.

On 6 August 2008, Rockstar announced a Windows version of GTA IV was in development. The game would release in North America on 18 November and in Europe three days later. It features the same content as the original game, in addition to enhanced multiplayer specifically for the PC.