Murder Mistaken is a 1952 thriller play by the British author Janet Green.

It first appeared at the Prince of Wales Theatre in Cardiff under the title Teddy Bare's Picnic.

[1] The West End cast included Derek Farr, Anthony Marlowe, Phyllis Morris, Iris Hoey, Brenda de Banzie, Patricia Burke and Rosalie Crutchley.

It appeared on Broadway under the alternative title Gently Does It, lasting for thirty seven performances at the Playhouse Theatre.

[3] In 1955 it was adapted into the film noir Cast a Dark Shadow directed by Lewis Gilbert and starring Dirk Bogarde, Margaret Lockwood and Kay Walsh.