Grand Theft Auto IV (abbreviated to GTA IV and GTA 4) 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 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 is due in August 2008 via Xbox Live.

The game is set in a re-imagined Liberty City, a fictional city based heavily on modern day New York City. It follows Niko Bellic, a Serbian veteran of the Bosnian War 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.

Following its release, the game received overwhelmingly positive reviews, and is the highest-rated video game of all-time, according to critic review aggregator Game Rankings. GTA IV sold about 3.6 million units on its first day of release and grossed more than $500 million in its first week, breaking the first-week sales record of $300 million set by Halo 3.