The present study examined whether age moderates the relationship between cognitive factors (theory of mind and attribution of intentions) and relational aggression. Participants (N = 426; 216 boys) between 6 and 9 years of age were asked to complete theory of mind tasks and answer an attribution of intentions questionnaire. Teachers evaluated their students' social behaviors including relational aggressive acts. Results suggest that theory of mind did affect relational aggression, when this association was moderated by chronological age. Specifically, it was found that the association between theory of mind and relational aggression was only significant and positive for younger participants; for older children the direction of this association was inverse. Taken together, findings from this study partially support the assertion that sophisticated cognitive skills are a prerequisite for indirect ways of aggression.