Roy Horniman (1874–1930) was a British writer.

He was the owner of The Ladies Review for some years and was a member of the British Committee of The Indian National Congress. As well as acting he became tenant and manager of the Criterion Theatre and wrote many plays as well as adaptations of his own and others’ novels. In his later years he wrote and adapted for the screen. Amongst his notable works were Israel Rank: The Autobiography of a Criminal (1907) which was republished by Faber Finds in 2008, on which the 1949 film Kind Hearts and Coronets was based, as well as the 2013 Broadway musical A Gentleman's Guide to Love and Murder. He also wrote The Sin of Atlantis in 1900 and Lord Cammarleigh’s Secret: A Fairy Story of To-Day in 1907.

Roy Horniman served in the Artists Rifles during the First World War.