The October Man is a 1947 mystery film/film noir starring John Mills and Joan Greenwood, written by novelist Eric Ambler, who also produced.

A man is suspected of murder, and the lingering effects of a brain injury he sustained in an earlier accident, as well as an intensive police investigation, make him begin to doubt whether he is innocent.

When a bus crashes due to faulty steering, passenger Jim Ackland (John Mills) sustains a serious brain injury and a young girl under his care is killed.

When he reluctantly accepts an invitation for a night out, he meets Jenny Carden (Joan Greenwood), the sister of his colleague Harry (Patrick Holt).

Police Inspector Godby (Frederick Piper) suspects he was another of Molly's boyfriends and that after falling in love with Jenny, he wanted to rid himself of a possible blackmailer.

In his New York Times review, Bosley Crowther called it a "second rate film" with "a first-rate actor [John Mills]...surrounded by a generally competent cast".