Assignment in Brittany is a 1943 war film directed by Jack Conway and starring French actor Jean-Pierre Aumont and Swedish actress Signe Hasso, both in their American film debuts. Also starring was American actress Susan Peters.

The film was adapted from a novel by Helen MacInnes, which was serialized in The Saturday Evening Post from May 2 to June 20, 1942, and also became a bestseller when published as a book. When MGM bought the screen rights in February 1942, the novel was titled "Cross Channel". The working title of this film was "Fire in the Night".