This study examined the relationships between family systems and high school students' career development. Family adaptability and family cohesion were considered as indicators of family function, and career attitude maturity was conceptualized as a representative factor explaining adolescents' career development. A total of 634 high school students participated in this study. Overall, the results showed that family adaptability and family cohesion were both significant predictors of tenth graders' career attitude maturity. The effects of parents' educational backgrounds on career attitude maturity were negligible. However, the relationships were inconsistent across gender. For female students, family cohesion was a more influential predictor of career attitude maturity than family adaptability, while the opposite pattern was observed for the male students. (Contains 6 tables and 3 figures.)