The present study strove to better understand the associations between the development of late adolescents' self-efficacy beliefs toward science, and vocational and academic adjustment (i.e., career decidedness, scientific interests, science achievement, and persistence in science), while considering the potential moderating role of gender. Participants were 411 late adolescents, all admitted in a science-related field in college. Notable developmental heterogeneity in science self-efficacy beliefs was found across the transition to college with 50% of students reporting high stable self-efficacy beliefs, 20% of students experiencing an increase in self-efficacy beliefs, and 30% a decrease. Girls enrolled in technological programs (biology and physics) were more likely than boys to experience increasing self-efficacy beliefs toward science. Overall, students with high stable or increasing self-efficacy trajectories reported the most positive academic and vocational outcomes. Evidence for a gender moderating effect was found for career decidedness, where experiencing increasing and high stable self-efficacy beliefs toward science was associated with a gradual clarification of one's vocational choice for girls but not for boys. (Contains 2 tables and 2 figures.)