2 limitations of past research on social adjustment were addressed: (1) the tendency to focus on forms of aggression that are typical of boys (e.g., overt aggression) and to neglect forms that are more typical of girls (e.g., relational aggression) and (2) the tendency to study negative behaviors (e.g., aggression), to the exclusion of positive behaviors (e.g., prosocial acts). Using a longitudinal design (n = 245; third- through sixth-grade children, 9-12 years old), assessments of children's relational aggression, overt aggression, prosocial behavior, and social adjustment were obtained at 3 points during the academic year. Findings showed that, as has been demonstrated in past research for overt aggression, individual differences in relational aggression were relatively stable over time. Additionally, relational aggression contributed uniquely to the prediction of future social maladjustment, beyond that predicted by overt aggression. Finally, prosocial behavior contributed unique information (beyond that provided by overt and relational aggression) to the prediction of future social adjustment.