- Country: USA
- Genres: Crime, Thriller
- Release: 1937-05-02
- Director: Lloyd Corrigan
- Writers: Tristram Tupper , Jack Moffitt , William A. Pierce
- Language: English | Italian
- Stars: Boris Karloff , Warren Hull , Jean Rogers , Alan Baxter , Hobart Cavanaugh , Samuel S. Hinds (1875–1948) , David Oliver , Ward Bond , Frank Reicher , Edwin Maxwell
- Runtime: 68 min
- Awards: 1 nomination
- AKA: Nachtschlüssel (Austria) , Alerte la nuit (France, French Republic) , 夜の鍵 (Japan) , Night Key , Night Key (Canada) , Chave Misteriosa (Portugal, Portuguese Republic) , Alerte la nuit (Belgium) , Magiczny klucz (Poland) , A Chave Noturna (Brazil) , Alarma en la ciudad (Spain) , Cheia de noapte (Romania) , Night Key (United States of America) , La chiave misteriosa (Italy) , De nachtsleutel (Netherlands the) , Night Key (United Kingdom) , Nattens Gaade (Denmark) , Nattens gåta (Sweden) , O Frankenstein aihmalotos (Greece) , Ночной ключ
- Plot: The inventor of a new top-of-the-line burglar alarm system is kidnapped by a gang in order to get him to help them commit robberies.
- IMDB:tt0029309
Night Key Cast · · · ALL
Lloyd Corrigan
Director
Boris Karloff
David Mallory
Warren Hull
Jim Travers
Jean Rogers
Joan Mallory
Alan Baxter
John Baron aka The Kid
Hobart Cavanaugh
Petty Louie
Samuel S. Hinds
(1875–1948)
Steven Ranger
David Oliver
Mike Callahan
Ward Bond
Fingers
Frank Reicher
Carl - gang engineer
Edwin Maxwell
Lawyer Kruger
George Cleveland
Sam Adams - Company Engineer (uncredited)
Ruth Fallows
Waitress (uncredited)
George Humbert
Mr. Spinelli (uncredited)
Nina Campana
Mrs. Spinelli (uncredited)
Charles C. Wilson
Police Capt. Wallace (uncredited)
Chuck Hamilton
(I)
(1903–1978)
Policeman (uncredited)