Written by Blanche Hanalis, the film is based on a story by Jane Trahey about an orthodox mother superior who is challenged by a progressive younger nun when they take the girls of St. Francis Academy on a bus trip across the United States.

The conservative Mother Superior and the glamorous, progressive young Sister George shepherd a busload of Catholic high-school girls from Pennsylvania to an interfaith youth rally in California.

During their long drive to California, the group experiences various difficulties including spending the night at an all-boys Catholic school, encountering hostile bikers and blundering onto an outdoor Western movie set, anachronistically ruining an important scene and reducing the excitable director (Milton Berle) to apoplexy.

Other scenes were filmed in the Lehigh Valley at Dorney Park and at St. Mary's Villa, a Catholic home for troubled youths on Bethlehem Pike in Ambler, Pennsylvania.

Composer Lalo Schifrin, best known for his work on the television series Mission: Impossible, collaborated with Boyce and Hart on the title song and supplied the incidental score.