Morf and Rhodewalt's self-regulatory model of narcissism (2001) posits that although the narcissistic sense of self is clearly inflated, it is also highly vulnerable. According to this model, people with narcissism are constantly concerned and motivated to maintain their inflated self-esteem through a variety of intrapersonal and interpersonal mechanisms. When faced with an ego threat, an individual with narcissism may use aggression as a mechanism to re-establish self-esteem and/or to punish the specific source of the threat. As such, aggressive narcissistic reactions may be an adaptive mechanism to regulate mood, motivation, and behavior. Survey studies have found associations between high scores on the Narcissistic Personality Inventory (NPI) and the experience and expression of anger, hostility, and dominance in young adults. The current study examined the associations of narcissism with aggression and internalizing symptoms among young adolescents. First, it examined the factor structure of the NPI with this population. Second, the study directly examined the associations of narcissism with self-reported, peer-reported, and teacher-reported aggression in young adolescents. A factor analysis of the sample's scores on the NPI revealed three factors: adaptive narcissism, exploitativeness, and exhibitionism. Regression analyses predicted the association of these three narcissistic features with aggression and internalizing symptoms. The findings show that narcissistic exploitativeness positively predicted self-reported proactive aggression, and narcissistic exhibitionism positively predicted internalizing symptoms. Narcissism and self-esteem interacted to predict teacher-reported aggression and self-reported internalizing symptoms. These findings are discussed with reference to existing theories of narcissism, threatened egotism, and self-perception bias. 5 tables, 2 figures, and 76 references