Yesterday's Enemy is a 1959 Hammer Films British war film in MegaScope directed by Val Guest and starring Stanley Baker, Guy Rolfe, Leo McKern and Gordon Jackson set in the Burma Campaign during World War II. It is based on a 1958 BBC teleplay by Peter R. Newman, who turned it into a three-act play in 1960. The TV play was reportedly based on a war crime perpetrated by a British army captain in Burma in 1942. Gordon Jackson repeated his role from the BBC teleplay as Sgt. Ian McKenzie.

Columbia Pictures co-produced the film with Hammer Films in an agreement for five co-productions a year with Columbia providing half the finance. The film, including extensive jungle and swamp scenes, was shot entirely on indoor sets in black and white and Megascope. The film has no musical score.

Director Val Guest later said that Yesterday's Enemy was one of his films of which he was the most proud. In 2013, film magazine Total Film included Yesterday's Enemy in their list of 50 Amazing Films You've Probably Never Seen.