Bark Psychosis are an English post-rock band/musical project from east London formed in 1986. They are one of the bands that Simon Reynolds cited when coining "post-rock" as a musical style in 1994, and are thus considered one of the key bands defining the genre.
In its original form, the group was a quartet of Graham Sutton, Daniel Gish, John Ling and Mark Simnett. This line-up recorded early singles and EPs plus the seminal 1994 album Hex, before gradually dissolving over the course of 1994, with Sutton moving on to his drum and bass project Boymerang and to production work. Sutton reformed Bark Psychosis in 2004 without any of the other previous members, as a flexible project in which he was supported by a shifting roster of guest musicians. Due to Sutton's renewed focus on production work, Bark Psychosis has been inactive since 2005, with no announcements of a final breakup or future plans.