The present study investigated the role of best friends in educational career development from adolescence to adulthood. Participants' (N=476) reciprocal best friendships were identified at age 15, while their educational attainment was investigated in early adulthood (age 26), their intelligence (IQ) at age 13, and parental education, educational expectations and academic achievement at age 16. The results revealed that adolescent best friends ended up pursuing similar educational careers in adulthood. Furthermore, three kinds of partner-effects were found when adolescents' prior career behaviors were controlled for: (1) best friends' intelligence predicted adolescents' later academic performance; (2) best friends' parental education predicted adolescents' educational expectations; and (3) best friends' educational expectations predicted adolescents' educational attainment in early adulthood. (Contains 1 table and 3 figures.)