The maladaptive personality and neuropsychological features of highly relationally aggressive females were examined in a group of 30 grade 6, 7, and 8 girls and group-matched controls. Employing a multistage cluster sampling procedure, a group of highly, yet almost exclusively, relationally aggressive females were identified and matched on a number of variables to a group of nonaggressive females. Parents of the students in both groups completed the Coolidge Personality and Neuropsychological Inventory, a 200-item DSM-IV-TR aligned, parent-as-respondent, standardized measure of children's psychological functioning. It was found that high levels of relational aggression, in the absence of physical and verbal aggression, were associated with symptoms of DSM-IV-TR Axis I oppositional defiant disorder and conduct disorder. The highly relationally aggressive group also exhibited a wide variety of personality traits associated with DSM-IV-TR Axis II paranoid, borderline, narcissistic, histrionic, schizotypal, and passive aggressive personality disorders that were not exhibited by the matched controls. Implications of these findings are discussed.