The Sign of Four may refer to:

• The Sign of the Four, a novel by Sir Arthur Conan Doyle featuring the fictional detective Sherlock Holmes
• The Sign of Four (1923 film), a silent film based on the novel, directed by Maurice Elvey
• The Sign of Four (1932 film), a film based on the novel, directed by Graham Cutts
• The Sign of Four (1983 film), one of a series of films based on the Sherlock Holmes novels made in the 1980s, starring Ian Richardson
• "The Sign of Four", one of a series of television programs collectively titled Sherlock Holmes, based on the Sherlock Holmes stories, starring Jeremy Brett
• The Sign of the Four (2001 film), a Hallmark Channel adaptation, starring Matt Frewer as Holmes
• The Sign of 4 (album), a collaborative free jazz album between guitarists Pat Metheny and Derek Bailey, and percussionists Gregg Bendian and Paul Wertico.

This disambiguation page lists articles associated with the title The Sign of Four.
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