The Blue Mountains Mystery is a lost 1921 Australian silent film directed by Raymond Longford and co-directed by Lottie Lyell.

Plot

The Blue Mountains Mystery involves the alleged murder of a wealthy businessman, Henry Tracey, and the eventual discovery that the victim was an underworld look-alike impersonator. The main suspects are Tracey's ward, Pauline, Mrs Tracey, and Pauline's boyfriend, Hector, and his rival, Richard Maxim.