They Knew Mr. Knight is a 1946 British drama film directed by Norman Walker and starring Mervyn Johns, Nora Swinburne and Joyce Howard.

A man is sentenced to twelve months in Lincoln jail following his involvement in a share scam, plunging himself and his family into despair.

It suffered a financial loss on its release and it was the last of four films that Walker made for Rank.

[2] The Radio Times gave the film two out of five stars, and wrote, "director Norman Walker rather wallows in this glum middle-class morality tale.

But he prudently cashes in on Johns's fretful features and the solid support provided by Nora Swinburne and Joan Greenwood, as his wife and self-sacrificing daughter.