Guy Stuart Ritchie is an English film director, producer and screenwriter. His work includes British gangster films, and the Sherlock Holmes films starring Robert Downey Jr.

A gangster film or gangster movie is a film belonging to a genre that focuses on gangs and organized crime. It is a subgenre of crime film, that may involve large criminal organizations, or small gangs formed to perform a certain illegal act. The genre is differentiated from Westerns and the gangs of that genre.