This document provides an overview of genre theory in film. It discusses how genres have existed since the early days of cinema and have a long history dating back to Ancient Greece. Genre theorists like Daniel Chandler and Steve Neale note that genres constitute conventions across a range of productions in terms of themes, settings, structure and style. The main genres of film are identified as action/adventure, crime, comedy, drama, thriller, epics, horror, musical, science fiction, war and western. Characteristics of genres are discussed in terms of visual imagery, style, characters, settings and narrative development. Expectations for genres like gangster, horror, musical, sci-fi, action and western are listed.