Sierra Sue is a 1941 American Western film directed by William Morgan and starring Gene Autry, Smiley Burnette, and Fay McKenzie. Written by Earl Felton and Julian Zimet, the film is about a government inspector investigating a poisonous weed that is destroying the rangeland supporting the area's cattle. The inspector must persuade the ranchers to reject a plan to burn the land and support a new process of chemical spraying from an airplane. The film features the popular Autry songs "Be Honest With Me", "Ridin' the Range", and the title track.

Eunice Fay McKenzie was an American actress and singer. She starred in silent films as a child, and then sound films as an adult, but perhaps she is best known for her leading roles opposite Gene Autry in the early 1940s in five horse opera features. She was also known for her collaborations with director Blake Edwards on five occasions.