Hapshash and the Coloured Coat was an influential British graphic design and avant-garde musical partnership in the late 1960s, consisting of Michael English and Nigel Waymouth. It produced popular psychedelic posters, and two albums of underground music.

The silkscreen printed posters created by the pair advertised underground "happenings", clubs and concerts in London, and became so popular at the time that they helped launch the commercial sale of posters as art, initially in fashionable stores such as the Indica Bookshop and Carnaby Street boutiques. Their first album of psychedelic music, produced by a collective in early 1967 and including many famous names, is now seen as being influential on the early works of Amon Düül and other pioneers of German Krautrock, as well as inspiring sections of the Rolling Stones' Their Satanic Majesties Request album.

Their posters remain highly sought after. The original artwork for a poster advertising Jimi Hendrix's 1967 concert at the Fillmore Auditorium in San Francisco – depicting the guitarist as a psychedelic Native American chief with a hunting bow in one hand and a peace pipe in the other – was sold in 2008 by Bonhams for $72,000. Between October 2000 and January 2001, the Victoria and Albert Museum, which owns the originals of many of their posters in its permanent collection, mounted a retrospective exhibition of their work titled "Cosmic Visions–Psychedelic Posters from the 1960s".