An English rock band formed by musician Steven Wilson in 1987. The band began essentially as a solo project for Wilson, who created all of the band's music. However, by 1993, Wilson desired to work in a band environment and so brought on frequent collaborators Richard Barbieri on keyboards, Colin Edwin on bass guitar and Chris Maitland on drums as permanent band members. With Wilson still in charge of guitar and lead vocals, this remained the lineup until 2001, when Gavin Harrison was recruited to replace Maitland on drums.

Porcupine Tree's early sound evokes a style of psychedelic rock comparable to that of progressive rock band Pink Floyd. Upon signing with Kscope record label in the late 1990s, the band approached a more mainstream alternative rock sound. By the early 2000s, the band signed to a major record label and shifted their sound again, this time in a more progressive metal direction.