The Fatal Witness is a 1945 American mystery film directed by Lesley Selander and written by Jerry Sackheim and Cleve F. Adams.

The film stars Evelyn Ankers, Richard Fraser, George Leigh, Barbara Everest, Barry Bernard and Frederick Worlock.

The wealthy Lady Elizabeth Ferguson threatens to disinherit nephew John Bedford after accusing him of stealing from her.

The dead body of Lady Elizabeth is discovered by her ward, Priscilla Ames, who phones Scotland Yard.

A suspicious Trent manages to persuade Priscilla to try an elaborate ruse, hiring actress Vera Cavanaugh to pretend to be Lady Elizabeth's ghost.