Copyright in the Sherlock Holmes stories expired in Canada in 1980.
The last copyright on ACD's work in the United Kingdom expired at the end of the year 2000.
In the United States, the only Sherlock Holmes remaining in copyright is portions of The Case Book. Three of the stories, published in 1921 through 1923, are already in the public domain; the rest will enter the public domain in various years leading up to 2023. A legal challenge that would have invalidated a 1998 extension to the length of copyright — putting Sherlock Holmes into the public domain immediately — was thrown out by the Supreme Court January 15, 2003.
The American copyrights are owned by Conan Doyle Estate Ltd. The American agent for administering them, and related rights in the Sherlock Holmes character, is Jon Lellenberg (Hazelbaker & Lellenberg, PO Box 32181, Santa Fe, New Mexico 87594), JonLellenberg@gmail.com. The British agent is Robert Kirby of United Agents (12-26 Lexington Street, London W1F 0LE), rkirby@unitedagents.co.uk. The Estate has a web page setting out its views about other claimants to those rights. For background, see a note by Peter Blau, January 2011.
On June 16, 2014, an American court (the United States Court of Appeals for the Seventh Circuit) upheld an earlier ruling from the District Court for the Northern District of Illinois regarding copyright protection, not for the stories themselves, but for the characters of Holmes and Watson. The defendant in the case was the Conan Doyle Estate Ltd. The plaintiff was well-known Sherlockian editor, and Los Angeles entertainment lawyer, Leslie S. Klinger. In the case of Klinger vs. Conan Doyle Estate Ltd., the appeals court ruling says that the "story elements" that stem from most of the stories — those published before 1923 — are in the public domain.
A web site for "the Sir Arthur Conan Doyle Literary Estate" represents Andrea Plunket, the former wife of Sheldon Reynolds, producer of the 1954 television series starring Ronald Howard as Holmes. Reynolds controlled the copyrights in the 1950s. Plunket is proprietor of a guest house in Livingston Manor, New York. Her claims to rights in the Sherlock Holmes stories have been repeatedly rejected in U.S. federal court decisions (including Plunket v. Doyle, No. 99-11006, Southern District of New York, February 22, 2001; Pannonia Farms Inc. v. ReMax International and Jon Lellenberg, No. 01-1697, District of Columbia, March 21, 2005). She has also filed a claim to the name "Sherlock Holmes" as a United States trademark, and that too has been turned down.
The “official website” at www.sherlockholmes.com represents the former proprietors of the Sherlock Holmes Memorabilia Company, who also own no rights to Arthur Conan Doyle works and characters. They have filed a U.S. trademark application, which has been blocked by formal Oppositions filed by the Estate and others.
The background of copyright and ownership issues around the writings of Arthur Conan Doyle is traced in a story in the New York Times January 18, 2010. (Also see this dissent and this editorial.)