Helping students adjust to university life is a critical developmental issue. Using longitudinal data from 1652 German late adolescents, this research tested the effect of initial high-school parent, same-sex, and opposite sex self-concept and its change on university dropout intentions, study stress, and study satisfaction. High-school self-concept predicted all outcomes. Change across the postschool transition in parent and same self-concept also predicted most outcomes. Change in opposite sex self-concept predicted no outcome. We argue young people's relationship self-beliefs are critical for successful developmental transitions. Consistent with previous research, we argue that parents remain a vital relationship for late adolescents.