This study investigated early adolescent friendship selection and social influence with regard to academic motivation (self-efficacy and intrinsic value), engagement (effortful and disruptive behavior), and achievement (GPA calculated from report card grades) among 6th graders (N = 587, 50% girls at Wave 1; N = 576, 52% girls at Wave 2) followed from fall to spring within 1 academic year. A stochastic actor-based model of social network analysis was used to overcome methodological limitations of prior research on friends, peer groups, and academic adjustment. Evidence that early adolescents sought out friends who were similar to themselves (selection) was found in regard to academic self-efficacy, and a similar trend was found for achievement. Evidence that friends became more similar to their friends over time (influence) was found for all aspects of academic adjustment except academic self-efficacy. Collectively, results indicate that selection effects were not as pervasive as influence effects in explaining similarity among friends in academic adjustment.