Tweaker is an American alternative rock collaboration founded by Chris Vrenna in the late 1990s. Tweaker's musical style incorporates synthpop, progressive rock, modern jazz and electronica genres, and is characterized by a generally melancholy and sombre sound with distinctive artwork to match.

The album The Attraction to All Things Uncertain was Vrenna's "solo" debut and it was not until the follow-up album, 2 a.m. Wakeup Call, that Clint Walsh was announced as a permanent fixture to the band. While Vrenna and Walsh supply most instruments and electronics, many other famous musicians have lent their voices and talents to Tweaker, including Robert Smith, David Sylvian, Burton C. Bell, Craig Wedren, Will Oldham, Hamilton Leithauser, Buzz Osborne, Jonathan Bates and Johnny Marr.

The albums that have been released follow a central theme that was planned out and this was given to the collaborators.

Tweaker wrote and performed the Soundtrack to Doom 3, Of which the theme song was released via the band's website. The rest of the soundtrack is accessible from the game's files.

As Chris Vrenna and Clint Walsh, Tweaker did music for the animated television show Xiaolin Showdown.

While the Doom 3 theme was Heavy Metal-oriented (to the point of often being misattributed to Tool), most of Tweaker's music presents a unique combination of synthpop, shoegaze, modern jazz, Dark Ambient and industrial.