Three-year longitudinal and concurrent associations of leadership with overt aggression, exclusion of others, effortful control (EC), popularity, unpopularity, prosocial behavior, and academic achievement were assessed in this study of Indonesian adolescents. Participants were initially assessed in the 10th grade (n = 462, 256 girls; M[subscript age] = 15.14, SD = 0.62) and followed for 2 years. Concurrent analyses revealed that leadership was positively associated with exclusion of others, EC, and popularity and negatively associated with overt aggression at 12th grade. The positive associations between leadership and exclusion of others only emerged for youth with high levels of EC. Positive associations of leadership with academic achievement were found in the longitudinal analyses and concurrent analyses at the 11th and 12th grade and concurrent associations between prosocial behavior and leadership were found each year. These findings reflect Indonesian cultural norms in which leaders are expected to maintain interpersonal harmony and avoid overt conflict.