John "Gus" Gustafson also known as Johnny Gustafson (8 August 1942 – 11 September 2014), was an English bass guitar player and singer, who had a lengthy recording and live performance career. During his career, he was a member of the bands The Big Three, Ian Gillan Band, Roxy Music and his own group, Quatermass, among others.
Gustafson was a member of Roxy Music for four years and performed on three studio albums. His final record with the band, Siren, included their only American hit single, "Love Is the Drug".
He was bassist on several tracks for Flamenco guitarist Juan Martin's 1981 concept album, Picasso Portraits (Flamencovision CD FV 03, 1994) namely: Harlequin – 1918, Desire Caught By The Tail – 1943, The Afficionado – 1912 and Girls of Algiers – 1955.