The authors examined how relational aggression, physical aggression, and proactive prosocial behavior were associated with jealousy and social anxiety in a diverse sample of 60 middle school students. After the authors controlled for gender and race, jealousy predicted relational aggression and proactive prosocial behavior, but it did not predict physical aggression. Additionally, social anxiety predicted proactive prosocial behavior. Adolescents who were more jealous in their peer relationships also tended to engage in relational aggression and proactive prosocial behavior, and adolescents who were more socially anxious also tended to be proactively prosocial. The authors discuss the implications of these findings and suggest directions for future research.