Objective: This study tested whether children’s symptoms of inattention and hyperactivity/impulsivity were associated with peer problems and whether these associations were mediated by conduct problems and prosocial behaviors. Method: A community sample of 500 children, including 245 boys and 255 girls, who ranged in age from 6 to 9 years (M = 7.6, SD = 0.91) were recruited. Teachers’ report of children’s inattention, hyperactivity/impulsivity, conduct problems, prosocial behaviors, and peer problems was collected. Results: Symptoms of inattention and hyperactivity/impulsivity were significantly positively associated with peer problems. Conduct problems were associated with more peer problems and prosocial behaviors with less peer problems. Conduct problems and prosocial behaviors partially mediated the association between hyperactivity/impulsivity and peer problems and fully mediated the inattention–peer problems association. Conclusion: Findings show that prosocial behaviors and conduct problems are important variables that account for some of the negative impact of symptoms of inattention and hyperactivity/impulsivity on peer functioning. (J. of Att. Dis. XXXX; XX(X) X-XX)