In film theory, film genre (/ˈʒɒnrə/ or /ˈdʒɒnrə/) refers to the method of categorizing films based on similarities in the narrative elements from which films are constructed or the emotional responses they elicit. Most theories of film genre are borrowed from literary genre criticism. Besides the basic distinction in genre between fiction and documentary (from which hybrid forms emerged founding new genres, docufiction and docudrama), film genres can be categorized in several ways.

The setting is the milieu or environment where the story and action takes place (e.g., a war film, a Western film or a space opera film). The theme or topic refers to the issues or concepts that the film revolves around (e.g., science fiction film, sports film or crime film). The mood is the emotional tone of the film (e.g., comedy film, horror film or tearjerker film). Format refers to the way the film was shot (e.g., anamorphic widescreen) or the manner of presentation (e.g.: 35 mm, 16 mm or 8 mm). Additional ways of categorizing film genres is by the target audience (e.g., children's film, teen film or women's film) or by type of production (e.g., B movie, big-budget blockbuster or low-budget film).