Frenzy is a 1972 British thriller film directed by Alfred Hitchcock. It is the penultimate feature film of his extensive career. The screenplay by Anthony Shaffer was based on the 1966 novel Goodbye Piccadilly, Farewell Leicester Square by Arthur La Bern. The film stars Jon Finch, Alec McCowen and Barry Foster and features Billie Whitelaw, Anna Massey, Barbara Leigh-Hunt, Bernard Cribbins and Vivien Merchant. The original music score was composed by Ron Goodwin.

The plot centres on a serial killer in contemporary London and the ex-RAF serviceman he implicates. In a very early scene there is dialogue that mentions two actual London serial murder cases: the Christie murders in the 1940s-1950s and the Jack the Ripper murders in 1888. Barry Foster has said that, in order to prepare for his role, he was asked by Hitchcock to study two books about Neville Heath, an English double murderer who would often pass himself off as an officer in the RAF.

Frenzy was the third and final film that Hitchcock made in Britain after he moved to Hollywood in 1939. The other two were Under Capricorn in 1949 and Stage Fright in 1950. (There were some interior and exterior scenes filmed in London for the 1956 remake of The Man Who Knew Too Much.) The last film he made in Britain before his move to the United States was Jamaica Inn (1939). Frenzy was the only Hitchcock film given an R rating during its initial release. Frenzy was screened at the 1972 Cannes Film Festival, but it was not entered into the main competition. Some critics – such as Raymond Foery, author of Alfred Hitchcock's Frenzy: The Last Masterpiece – consider Frenzy the last great Hitchcock film, and a return to form after his two previous works: Topaz and Torn Curtain.