This longitudinal study investigated the role of parents and peers as well as of education-related goal motivation during educational transitioning in late adolescence. The sample consisted of 1520 upper secondary education students attending either academic or vocational upper secondary school in Finland. They were surveyed three times: (1) in the first year of their upper secondary education, (2) in the second year of their upper secondary education, and (3) two years later. The results show, first, that when students in upper secondary education pursued their educational goals out of autonomous motivation they also invested more effort in their goals, which was reflected in high levels of goal progress. High goal progress, in turn, was related to high levels of school satisfaction, whereas low goal progress was associated with the intention to drop out of school. By contrast, controlled motivation was associated neither with goal effort or goal progress in educational goals. Second, different interpersonal environments played unique and different roles in adolescents’ educational goals. While mothers’ affective warmth and involvement particularly enhanced adolescents’ autonomous motivation, fathers’ affective support directly predicted high levels of school satisfaction and low intentions to drop out of upper secondary school. The role of peer acceptance (measured using a sociometric procedure) was twofold: it was related to high autonomous motivation in adolescents’ educational goals, and it also directly predicted adolescents’ satisfaction with their chosen educational track. The intention to drop out of school is an important warning signal of later actually dropping out. Additional analyses showed that the less adolescents had the intention to drop out of upper secondary school, the more likely they were to be successful in dealing with the educational transition from upper secondary school to further education or employment.