The purpose of the present study was to identify clinically relevant subtypes of aggressive children based on measures of children's self-systems and significant others' perceptions of relationship quality. In a sample of aggressive second- and third-graders, a cluster analysis of these children's perceptions of support and significant others' (mother, teacher, and peers) perceptions of relationship quality revealed one subgroup in which self- and other-ratings were both below the group mean (concordant-negative), one in which both were above the sample mean (concordant-positive), and one in which they were discrepant (high child-report and low other-report). All three clusters were rated as more aggressive than controls. However, children in the discrepant group were rated as considerably more aggressive and delinquent than those in the two concordant clusters, who did not differ from each other on measures of internalizing and externalizing behaviors. Results are discussed from an attachment perspective and in terms of the clinical significance of this self–other discrepancy.