Three Smart Girls Grow Up is a 1939 American musical comedy film directed by Henry Koster and starring Deanna Durbin, Nan Grey, and Helen Parrish. Written by Felix Jackson and Bruce Manning, the film is about three sisters who believe life is going to be easy now that their parents are back together, until one sister falls in love with another's fiance, and the youngest sister plays matchmaker. Durbin and Grey reprise their roles from Three Smart Girls, and Parrish replaces Barbara Read in the role of the middle sister.