Seven (often stylized as Se7en) is a 1995 American crime thriller film directed by David Fincher and written by Andrew Kevin Walker. It stars Brad Pitt and Morgan Freeman, with Gwyneth Paltrow, and John C. McGinley in supporting roles. Set in an unnamed, crime-ridden city, Seven's narrative follows disenchanted, nearly retired detective William Somerset (Freeman) and his newly transferred partner David Mills (Pitt) as they try to stop a serial killer from committing a series of murders based on the seven deadly sins.

Walker, an aspiring writer, based Seven on his experiences of moving from a suburban setting to New York City during a period of rising crime and drug addiction in the late 1980s. An Italian film company optioned his script, but following financial difficulties, the rights were sold to New Line Cinema. Studio executives were opposed to the script's bleak conclusion, insisting on a more mainstream and optimistic outcome. Fincher, determined to re-establish himself after a career setback with his directorial debut Alien 3 (1992), was mistakenly sent Walker's original script and, convinced of its merit, committed to directing the project if the original ending remained intact. Principal photography took place in Los Angeles between December 1994 and March 1995, on a $33–$34 million budget.

Seven garnered middling test audience results and was not predicted to perform well due to its violent and mature content. However, it grossed $327.3 million worldwide, becoming a sleeper hit and the seventh highest-grossing film of the year. Contemporaneous reviews were generally positive, praising the performances of the central cast and the ending. Seven revitalized Fincher's career and helped Pitt move from roles based on his appearance to more serious, dramatic roles.

In the years since its release, the critical reception has been more positive. The film has inspired a number of TV series and films with its aesthetic, music, and premise. Its title sequence, which depicts the killer preparing for his actions in the film, is considered an important design innovation that sparked a renewed interest in title design, while the film's twist ending has been named as one of the most shocking and unforgettable in cinematic history.