Researchers continue to debate the role of self-esteem in aggression, but research has shown a consistent association between narcissism and aggression in adults and adolescents [e.g., Barry et al., 2007; Bushman and Baumeister, 1998; Stucke, 2007]. The primary aim of the current study was to examine whether locus of control (LOC) moderated the relation between self-perception variables (i.e., self-esteem and narcissism) and aggression in adolescents. Participants were 174 youth (145 males, 26 females) between the ages of 16 and 19 who were enrolled in a voluntary residential program for youth who have dropped out of school. The results showed that LOC moderated the association between self-esteem and aggression such that low self-esteem was associated with higher levels of aggression for individuals with an external LOC. Contrary to expectations, LOC failed to moderate the narcissism–aggression relation. The implications of this study for understanding how self-perception is related to adolescent aggression are discussed. Aggr. Behav. 38:213–221, 2012. © 2012 Wiley Periodicals, Inc.