During emerging adulthood (ages 18 through the mid-twenties), parents and siblings become more peripheral in daily life compared to earlier in development. While family relationship quality often improves significantly during the initial transition to emerging adulthood, less is known about how these relationships function and impact development across this period, especially for college students who may remain closer to their families due to financial need. The present study, therefore, examined longitudinal changes in parent-child and sibling relationships from the first to the fourth years of college, as well as longitudinal associations between family relationship qualities and emotional adjustment and academic/vocational adjustment. Study 1 included first- and second-born college students (between-families), while Study 2 included first-born college students and their second-born adolescent siblings (within-families). Overall, parent-child relationship quality was mostly stable across emerging adulthood, while sibling relationships experienced dynamic changes in power structure, as well as increased communication and self-disclosure. Family relationships also had positive implications for emotional and academic adjustment, but receiving high levels of financial assistance from parents was detrimental for these outcomes. Future research should further investigate the implications of parental financial assistance, and ways the family can promote healthy autonomy development for emerging adults.