Once a Thief is a 1991 film by John Woo. It stars Chow Yun-Fat, Leslie Cheung, Cherie Chung and Kenneth Tsang .

The story is of three orphans who are taken in by a wealthy crime boss (Tsang) which leads to their close friendship. The trio grow up learning high-tech methods of theft and specialised in stealing treasured paintings, however when they become adults, their then boy's rivalry for the affections of their beautiful sister (Chung) gets out of hand.

See also: The remake: Once a Thief (1996). The movie was remade with Nicholas Lea and Ivan Sergei , and was spun-off into a Canadian television series which ran from 1997 to 1998.