There is substantial evidence to suggest that aggressive behavior is associated with poor academic performance in school-aged children. However, less is known about how different subtypes of aggression are related to academic performance and what variables may account for this association. The current study examined unique associations between reactive (aggression in response to provocation) and proactive (goal-oriented calculated aggression) subtypes of aggression and academic performance. Further, the study evaluated whether peer rejection accounted for the link between these aggression subtypes and academic problems. Study questions were examined using a sample of 147 school-age children (M = 8.22, SD = 1.99, 54.4 % male) who attended a community-based after school program. Path models were used to estimate the proposed associations using Mplus 6.12 statistical software. As expected, findings indicated that high levels of reactive, not proactive, aggression were uniquely associated with low levels of academic performance, and peer rejection accounted for this association. Results advance the literature linking aggression and academic difficulties by indicating that reactive aggression, but not proactive aggression, is associated with academic difficulties. Findings also support previous literature suggesting that peer relationships are an important target of prevention and intervention efforts aimed at improving school performance, particularly for individuals who exhibit reactively aggressive behavior.