Triangle (simplified Chinese: 铁三角; traditional Chinese: 鐵三角; pinyin: tie san jiao) is a 2007 Hong Kong action film produced and directed by Tsui Hark, Ringo Lam, and Johnnie To. The film's title refers to both the acclaimed trio of filmmakers and to the uneasy brotherhood of the film's three protagonists. Triangle tells one story which is told in three thirty-minute segments, independently helmed by the three directors. It stars Louis Koo, Simon Yam and Sun Honglei as a group of friends who uncover a hidden treasure that quickly draws attention among others. The film's tagline is "Temptation. Jealousy. Destiny." Each word is often associated with the segments that appear in chronological order.

The first Hong Kong film made in a frame story format, Triangle had each director take charge of a film segment, bringing in their own production team and screenwriters to continue the story set in motion by the previous director. Critics made easy notice of the lack of continuity in between each segment, since the trio of directors did not share their scripts together while discussing the concepts.

Triangle was screened out of competition at the 2007 Cannes Film Festival. It was later released in China on 1 October 2007, which was one month before its theatrical Hong Kong release.