John Butcher (born 1954 in Brighton, England) is an English tenor and soprano saxophone player who has lived in London since the late 1970s. He began playing at the University of Surrey where he was studying physics. He received his PhD in theoretical physics with his thesis published as Spin effects in the production and weak decay of heavy Quarks. After that he left academia to focus on music. He began by playing conventional jazz (he has spoken of his initial skepticism concerning free improvisation), but quickly converted to a freer approach. He has taken the concern with the manipulation of multiphonics (split tones and false notes) bequeathed by earlier improvisers such as Evan Parker in new directions: though his earlier albums could be busy at times, he has come increasingly to focus on creating rich, slowly changing strata of sounds (layers of hums, buzzes and brittle metallic noises). He has also experimented with the use of amplified saxophone and overdubbing (most notably on the solo album Invisible Ear). That said, he is also capable of playing quite lyrically: on soprano, especially, he will sometimes leaven a passage of abstraction with bursts of pennywhistle-like melody.

Butcher worked with Elton Dean, Chris Burn, and Jon Corbett at first. Later he formed a trio with guitarist John Russell and violinist Phil Durrant, which recorded three albums and also served as the nucleus of News from the Shed, a shorter-lived quintet with Paul Lovens and Radu Malfatti. Another key relationship has been with singer Phil Minton, which included Butcher's participation in mouthfull of ecstacy, Minton's setting of texts from James Joyce's Finnegans Wake. More recently he has become centrally involved in the form of rarefied, minimalist improvisation that has been dubbed "electroacoustic improvisation" or "lowercase", most notably as a member of the pioneering Austrian group Polwechsel. Other playing partners have included John Edwards, Simon Fell, Gino Robair, Georg Gräwe, Gerry Hemingway, and Dylan van der Schyff. A recent, self-released album, Cavern with Nightlife, included a duet with no-input-mixing-board specialist Toshimaru Nakamura. Butcher's octet "John Butcher Group" debuted in 2008 at the Huddersfield Contemporary Music Festival.