Thriller is a genre of fiction with numerous, often overlapping, subgenres, including crime, horror, and detective fiction. Thrillers are characterized and defined by the moods they elicit, giving their audiences heightened feelings of suspense, excitement, surprise, anticipation and anxiety.

Horror films may incorporate incidents of physical violence and psychological terror; they may be studies of deformed, disturbed, psychotic, or evil characters; stories of terrifying monsters or malevolent animals; or mystery thrillers that use atmosphere to build suspense.