This study sought to determine if a six session classroom intervention coupled with a teacher education program was sufficient to alter behaviors related to socially aggressive behaviors of fourth grade students. The treatment manual for this intervention was developed by Pamela McDonald Schaber and Daniel Hoard (Schaber and Hoard, 2006), following a review of the literature on ecological intervention for overt and social/relational aggression. The objectives of the intervention were to reduce aggressive behaviors through an ecological approach by: (1) educating students on types of bullying (physical and social), the role of the bystander in contributing to bullying, and the consequences for individuals and the classroom environment when bullying occurs; (2) challenging sympathetic attitudes about the appropriateness of bullying; (3) providing students with strategies for intervening when they observe bullying; (4) modeling bystander interventions; (5) giving students an opportunity to practice bystander interventions; and (6) empowering classrooms to develop a code of conduct for working together to reduce bullying. Participants were 71 fourth grade students from a Central Texas elementary school. Participants completed the Social Experiences Questionnaire - peer-report which is a peer-rating measure of their classmates' frequency of social aggression and prosocial behavior. They also completed the Participant Roles Questionnaire - self-report to determine how often they engaged in the different roles associated with bullying (i.e., bully, defender, assistant...). The main findings were that social aggression decreased for boys but not girls, and bully behavior decreased for both boys and girls. Unexpected findings were that prosocial behavior decreased from pre-test to post-test, and there were no changes evidenced in defender, assistant, and reinforcer behaviors. Implications and limitations for the findings are provided.