English rock bassist, born 30 July 1946 in Blackpool.

A close friend of Ian Anderson since their teenage years, Jeffrey Hammond was called to replace Glenn Cornick as Jethro Tull's bass player in 1971. He recorded five albums with Tull, then left the band in 1975 to pursue a career as a painter. He is often credited as Jeffrey Hammond-Hammond because, coincidentally, his mother's name was also Hammond. He is also the Jeffrey mentioned in three early Jethro Tull song titles.