The effects of cognitive-behavioral group therapy on adolescent aggressive behavior were examined. Participants included 11 adolescent boys (6 African American and 5 white). The Youth Self Report, the Child Behavior Checklist, and the Piers-Harris Children's Self-Concept Scale were administered pretest (before group therapy) and posttest (after group therapy). Results revealed that adolescents reported statistically significant changes in aggressive behavior, attentional problems, somatic complaints, anxious/depressed behavior, and perceptions of intellectual and school achievement and status. Parents reported clinical changes in adolescent aggressive behavior, albeit not at the level of statistical significance. These findings suggest that group therapy can be an important mechanism to help adolescents examine their attributional biases and alter maladaptive patterns of interpersonal conflict.