This study examined whether children’s social behavior mediated the associations between specific dimensions of temperament and peer acceptance, and whether these associations were moderated by gender. We also explored the role of child’s age on the associations between temperament and social functioning. Primary caregiver reports of temperament and peer reports of social behavior and peer acceptance were obtained for 140 boys and 135 girls (8–16 years, M = 11.9) from 275 different classrooms. Dimensions of temperament reflecting general activity, flexibility-rigidity, and attentional focus were found to be particularly important to children’s social functioning at school, and their associations with peer acceptance were found to be significantly mediated by social behaviors. Additionally, we found that while linkages between dimensions of temperament and social acceptance were present for boys and girls, the pathways (mediators) were often different. Our exploratory analyses suggested that linkages between temperament and social functioning are strong for younger children, but less so for older youth. Findings are discussed in the context of their implications for theory and clinical applications, emphasizing the importance of considering gender differences in the contributions of temperament to social functioning.