As the first Sherlock Holmes story published, A Study in Scarlet was among the first to be adapted to the screen. In 1914, Conan Doyle authorised a silent film be produced by G. B. Samuelson. Holmes was played by James Bragington, an accountant who had never before (and never after) worked as an actor. He was hired for his resemblance to Holmes as presented in the sketches originally published with the story. As early silent films were made with film which itself was made with poor materials and film archiving was rare, this is now a lost film. The success of this film allowed for a second version to be produced that same year by Francis Ford, which has also been lost.
The 1933 film entitled A Study in Scarlet, starring Reginald Owen as Sherlock Holmes and Anna May Wong as Mrs Pyke, bears no plot relation to the novel, the producers having only purchased rights to the title, not the story. (So limited were the purchased rights, that the famous Baker Street address is "221A" in the film rather than the renowned "221B.") Aside from Holmes, Watson, Mrs. Hudson, and Inspector Lestrade, the only connections to the Holmes canon are a few lifts of character names (Jabez Wilson, etc.). The plot contains an element of striking resemblance to one used several years later in Agatha Christie's novel And Then There Were None, that of murder victims being counted off by lines from the same nursery rhyme (though the Holmes film takes the precaution of using the phrase "ten little black boys").
The book has rarely been adapted in full, notable instances being: an episode broadcast on 23 September 1968 in the second season of the BBC television series Sherlock Holmes, with Peter Cushing in the lead role and Nigel Stock as Dr. Watson, which put more detail into the story, including the actor who claims the ring; the first episode of the 1979 Soviet TV adaptation, Sherlock Holmes and Dr. Watson (The first episode combines the story of their meeting with The Adventure of the Speckled Band. The second episode adapts the actual Jefferson Hope case.); an 1983 animated version produced by Burbank Films Australia, with Peter O'Toole voicing Holmes; Sherlock Holmes and a Study in Scarlet the first episode of the BBC's complete Sherlock Holmes on Radio 4, starring Clive Merrison as Holmes and Michael Williams as Watson; and a 2007 episode of the American radio series The Classic Adventures of Sherlock Holmes.
In the Peter Cushing 1968 adaptation and the 1983 animated version, the story is changed so that Holmes and Watson already know each other and have been living at 221-B Baker Street for some time.
Other adaptations use only the portions of the first section of the book in which Holmes and Watson's relationship is established. The Ronald Howard/H. Marion Crawford television series used that section of the book as the basis for the episode "The Case of the Cunningham Heritage". The John Gielgud/Ralph Richardson radio series combined it with details from "The Adventure of Charles Augustus Milverton" to create its "origin story".
Steven Moffat loosely adapted A Study in Scarlet into "A Study in Pink" as the first episode of the 2010 BBC television series Sherlock featuring Benedict Cumberbatch as a 21st-century Sherlock Holmes, and Martin Freeman as Dr. Watson. The adaptation retains many individual elements from the story, such as the scribbled "RACHE" and the two pills, and the killer's potentially fatal aneurysm (however it is located in his brain rather than his aorta). However, the entire backstory set in America is omitted, and the motivation of the killer is completely different. It also features Moriarty's presence.
In 2010, A Study in Scarlet was adapted for the stage by William Amos Jr and Margaret Walther.
In 2014, A Study in Scarlet was adapted again for the stage by Greg Freeman, Lila Whelan and Annabelle Brown in an adaptation for Tacit Theatre. The production premiered at Southwark Playhouse in London in March 2014
"The Deductionist", an episode of Elementary contains many elements of Hope's case, including the motivation of revenge.
In 2014 NHK puppetry Sherlock Holmes, the series' first episode "The First Adventure" is loosely based on A Study in Scarlet and "The Adventure of the Six Napoleons". In it, Holmes, Watson and Lestrade are pupils of a fictional boarding school Beeton School and they find out that a pupil called Jefferson Hope revenges on Enoch Drebber and Joseph Stangerson for robbing his watch. And "Scarlet Story", title of an opening theme of the series is named after the novel and the name of "Beeton School" is partially after Beeton's Christmas Annual.
A Study in Scarlet was illustrated by Seymour Moskowitz for Classics Illustrated comics in 1953. It was also adapted to graphic novel form by Innovation Publishing in 1989 (adapted by James Stenstrum and illustrated by Noly Panaligan) and by Sterling Publishing in 2010 (adapted by Ian Edginton and illustrated by I.N.J. Culbard).