Frank Denyer (born April 12, 1943 in London) is a composer. His music uses a combination of conventional instruments and new, unusual, and structurally modified instruments. Partly due to his studies of non-Western music, much of Denyer's music is microtonal.
Denyer was a chorister at Canterbury Cathedral and later studied at the Guildhall in London. In 1966 he co-founded, and was director of, the Society of Hermes, an arts club for new music, painting, poetry and theatre in Shepherds Bush, London. He formed and directed Mouth of Hermes. a professional instrumental ensemble devoted to new and experimental forms of music. He toured widely with the ensemble in Europe, Scandinavia and the U.K. in the years up to 1974, presenting new compositions. During this time he was Lecturer in Composition and 20th Century Studies at Hornsey College of Art. This early period culminated in his being a featured composer/performer at the Festival d’Orleans, France, in 1973.