The study investigated the effects of reappraisal training on aggressive children. A pre–post–follow-up, experimental–control design was used to evaluate the impact of a small-group intervention that offered practice in reappraisal skills to 89 aggressive children (another 60 were wait-listed). Results indicate that treatment children benefitted in these skills more than their peers. Based on multiple sources of the report (child, parent, teacher), results also point to reduced aggression, anger, anxiety, and social problems, and an increase in self-regulation, all of which sustained at follow-up 7–8 months later. Finally, many outcomes were correlated with benefits in reappraisal skills. Qualitative data gleaned from the study supports these benefits and sheds light on group processes that were helpful. The findings suggest that reappraisal skills training is a useful intervention with aggressive children and can be successfully delivered in small groups.