Adolescents with conduct disorder frequently engage in aggressive and disruptive behaviors. Often these behaviors are controlled or managed through behavioral or other psychosocial interventions. However, such interventions do not always ensure lasting changes in an adolescent's response repertoire so that he or she does not engage in aggression when exposed to the same situations that gave rise to the behavior previously. Mindfulness training provides a treatment option that helps an individual focus and attend to conditions that give rise to maladaptive behavior. Using a multiple baseline design, we assessed the effectiveness of a mindfulness training procedure in modulating the aggressive behavior of three adolescents who were at risk of expulsion from school because of this behavior. The adolescents were able to learn the mindfulness procedure successfully and use it in situations that previously occasioned aggressive behavior. This led to large decreases in the aggression of all three individuals. Follow-up data showed that the adolescents were able to keep their aggressive behavior at socially acceptable levels in school through to graduation. Maladaptive behaviors, other than aggression, that the adolescents chose not to modify, showed no consistent change during mindfulness training, practice, and follow-up.