We evaluated links between peer-group functioning and indicators of attachment security in relation to both mother and father in middle childhood, among 73 10-year-olds (37 girls). Children's perceptions of security with both parents, coping styles with mother, and self-worth were assessed. Classmates, teachers, and mothers evaluated the participants' peer-related behavioral characteristics. Children's perceptions of security to both parents were related to others' appraisals of their social competence; perceptions of security to father were related to lower aggression. We did not find child gender effects, but children had higher security scores in relation to mother than to father. Self-worth perceptions mediated the relation between attachment and social competence.