.hack//G.U.

.hack//G.U. is a series of single-player action role-playing games for the , developed by CyberConnect2 and published by Bandai Namco Entertainment between 2006 and 2007. The series contains three games: .hack//G.U. Vol. 1//Rebirth, .hack//G.U. Vol. 2//Reminisce and .hack//G.U. Vol. 3//Redemption. As in the previous .hack games, .hack//G.U. simulates a massively multiplayer online role-playing game (MMORPG) called The World—the player controls a character who plays the fictional online game. They were directed by Hiroshi Matsuyama who aimed to address criticisms of the previous series. Its narrative, by Tatsuya Hamazaki, was written concurrently with .hack//Roots, an anime set before the events of the games produced by Bee Train, which depicts Haseo's first days in The World. However, due to narrative and character discontinuity resultant from Roots being written by a completely different production team than the games, manga and novels released as part of G.U., Cyberconnect2 now considers the prequel anime to be one of the non-canon entries within the .Hack Franchise.

The series has also been adapted into a manga, a light novel, and an animated film.