Gaston Louis Alfred Leroux (6 May 1868 – 15 April 1927) was a French journalist and author of detective fiction.
In the English-speaking world, he is best known for writing the novel The Phantom of the Opera (Le Fantôme de l’Opéra, 1910), which has been made into several film and stage productions of the same name, notably the 1925 film starring Lon Chaney, and Andrew Lloyd Webber’s 1986 musical. His novel The Mystery of the Yellow Room is one of the most celebrated locked-room mysteries.
In 1919, he and Arthur Bernède formed their own film company, Société des Cinéromans, publishing novels and turning them into films. He first wrote a mystery novel titled Le mystère de la chambre jaune (1908; English title: The Mystery of the Yellow Room), starring the amateur detective Joseph Rouletabille. Leroux’s contribution to French detective fiction is considered a parallel to those of Sir Arthur Conan Doyle in the United Kingdom and Edgar Allan Poe in the United States.
Leroux published his most famous work, The Phantom of the Opera, as a serial in 1909 and 1910, and as a book in 1910 (with an English translation appearing in 1911).