The Third Secret is a 1964 British CinemaScope neo-noir psychological mystery thriller film directed by Charles Crichton, and starring Stephen Boyd, Jack Hawkins, Richard Attenborough, Diane Cilento, Pamela Franklin, Paul Rogers and Alan Webb.

Prominent London psychoanalyst Dr. Leo Whitset is discovered injured from a gunshot wound in his home by his housekeeper, and as he lies dying he whispers, "blame no one but me".

Sir Frederick Belline is a respected judge, Alfred Price-Gorham runs a prestigious art gallery with his assistant Miss Humphries, and Anne Tanner is a corporate secretary.

There he learns Catherine was under her father's care, and when he confronts her, she admits she killed the doctor when he threatened to send her to an institution to be treated for paranoid schizophrenia.

[5] The Monthly Film Bulletin wrote: "Distressingly but understandably at a loss with much of Robert L. Joseph's aimless and obscure scenario, Crichton does what he can to keep up visual interest on the psychological thriller level.

Stephen Boyd sees it through with an appropriate air of puzzled innocence, quite acceptably accompanied by a maturing Pamela Franklin; in vignette appearances, Jack Hawkins and Diane Cilento battle valiantly against cruel mishandling and impossible lines.

Richard Attenborough transforms the film for a few brief moments by making the utmost of his completely irrelevant role as the art dealer; he achieves a portrait both amusing and pathetic of a weak but vain man struggling desperately to justify his existence.