The Killer (Chinese: 喋血雙雄) is a 1989 Hong Kong action film directed and written by John Woo and produced by Tsui Hark. The film stars Chow Yun-fat, Danny Lee and Sally Yeh. Chow plays Ah Jong, a professional assassin for the Triads who wants to retire, but accidentally damages the eyes of singer Jennie (Yeh) during a shootout and sets out to perform one last hit to pay for her treatment.

After the financial backing from Hark became problematic following the release of Woo's film A Better Tomorrow 2, Woo had to find backing through Chow Yun-fat's and Danny Lee's financing companies. Woo went into filming The Killer with a rough draft whose plot was influenced by the films Le Samouraï, Mean Streets and Narazumono. Woo wanted to make a film about honour, friendship and the relationship of two seemingly opposite people. After finishing filming, Woo referred to The Killer as a tribute to directors Jean-Pierre Melville and Martin Scorsese.

The Killer was not an immediate success in Hong Kong but received critical acclaim internationally with reviewers praising its action scenes and over-the-top style. The film became Woo's steppingstone into Hollywood and has been a strong influence on many directors, including Quentin Tarantino, Robert Rodriguez and Johnnie To. In the years since, The Killer has come to be considered one of the greatest action films ever made. An English-language remake of the film, also directed by Woo, was released in August 2024.