The Balanescu Quartet is a London-based avant-garde string quartet founded in 1987 by Romanian-born violinist Alexander Bălănescu. The group achieved fame through the release of Possessed, consisting of complex cover versions of songs by German experimental electronic music band Kraftwerk.

The driving force behind the quartet has always been main composer and founder Alexander Balanescu.

The quartet are mainly notable for their very distinctive style of music, which encompasses odd time rhythms, sound dissonances and complex arrangements. The band has performed multiple works with a variety of other artists, including David Byrne, Gavin Bryars, Michael Nyman, Rabih Abou-Khalil, Kevin Volans, Hector Zazou, and Spiritualized.

They are the performers of the current arrangement of University Challenge's title music on BBC2 in the U.K.

They are currently signed to Mute Records. Their early albums were on Argo Records (UK).