Frederick Walter Stephen West (29 September 1941 – 1 January 1995) was an English serial killer who committed at least twelve murders between 1967 and 1987 in Gloucestershire, the majority with his second wife, Rosemary West.

All the victims were young women. At least eight of these murders involved the Wests' sexual gratification and included rape, bondage, torture and mutilation; the victims' dismembered bodies were typically buried in the cellar or garden of the Wests' Cromwell Street home in Gloucester, which became known as the "House of Horrors". Fred is known to have committed at least two murders on his own, while Rose is known to have murdered Fred's stepdaughter, Charmaine. The couple were arrested and charged in 1994.

Fred fatally asphyxiated himself while detained on remand at HM Prison Birmingham on 1 January 1995, at which time he and Rose were jointly charged with nine murders, and he with three further murders. In November 1995, Rose was convicted of ten murders and sentenced to ten life terms with a whole life order.