Doctor Syn (Dr. Syn in the United States) is a 1937 British black-and-white historical dramatic adventure film, directed by Roy William Neill for Gainsborough Pictures. It stars George Arliss (in his last feature film), Margaret Lockwood, Graham Moffatt, and Ronald Shiner. The film is based on the Doctor Syn novels of Russell Thorndike, set in 18th century Kent. The character of Syn and the events at the film's climax were both softened considerably in comparison to Thorndike's original storyline.