Possum is a 2018 British psychological horror film written and directed by Matthew Holness in his feature film debut, starring Sean Harris and Alun Armstrong. It centres on a disgraced children's puppeteer who returns to his childhood home and is forced to confront trauma he suffered there.

Possum is an adaption of Holness' short story of the same name, published in the horror anthology The New Uncanny: Tales of Unease, and partially inspired by the theories on the uncanny by Sigmund Freud. Holness soon forgot about the idea of adapting the story until he had begun working on developing a possible horror film. As a fan of the horror genre, Holness stated he much preferred horror films that resonate with the audience and force them to reflect on the experience afterward. Possum's visual style was inspired by public information films Holness saw in his youth. Other inspirations include Dead of Night (1945), George A. Romero's Martin (1978), and German Expressionist films. Filming began in Norfolk, with additional filming taking place in Great Yarmouth and Suffolk. The film's score was composed by sound effects and experimental electronic music studio The Radiophonic Workshop, which marked their first soundtrack purposely constructed for a feature film.

Possum premiered at the Edinburgh International Film Festival on 25 June 2018, and later screened in the United States at the Brooklyn Horror Film Festival on 12 October 2018. It was later given a limited theatrical release in the United States, opening in five theatres on 2 November 2018; finishing its limited theatrical run with a gross of $33,271. Later, it was given a home media release. In addition to garnering multiple awards and nominations, it was generally praised by critics for Harris' performance, the film's atmosphere, score, and unsettling imagery, though the story prompted some criticism.