Rainbow Valley is a 1935 American Western film released by Monogram Pictures, written by Lindsley Parsons, directed by Robert N. Bradbury and starring John Wayne and Gabby Hayes.

Riding to the small town of Rainbow Valley, John Martin meets George, the mailman for the area, who is looking for water for his car.

Eleanor, the postmistress, is suspicious of Martin, but George explains how he fought off the gang.

They are circulating a petition to the governor for assistance in completing their road and ridding it of the gang, which is led by Rogers, a wealthy landowner whose goal is to drive out the townspeople and buy their land cheaply.

Martin went to school for engineering, and volunteers to take charge of the road work.