The Third Secret
- Blwyddyn: 1964
- Gwlad: United Kingdom
- Genre: Mystery, Thriller, Drama
- Stiwdio: Hubris Productions
- Allweddair: london, england, schizophrenia, film noir, psychologist, american abroad, killer child, tv host
- Cyfarwyddwr: Charles Crichton
- Cast: Stephen Boyd, Jack Hawkins, Richard Attenborough, Diane Cilento, Pamela Franklin, Paul Rogers