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