Bullying victimization is a school problem that warrants attention. While most work has focused on understanding bullies and victims, it is important that research explore how to promote bystander behavior during bullying as a mechanism to deter bullying in schools. Perceptions of the school climate may impact the likelihood of a student's willingness to intervene. In addition, research has suggested that the bystander intervention model (BIM) can also impact bystander behavior. The present study examined the relationship between school climate and BIM in relation to defending and outsider behavior in youth with a diverse sample of 199 middle school students. The results of this study demonstrated a significant relationship between students' knowledge of the BIM and both defending and outsider behavior. School climate was found to have a marginally significant effect on the relationship between BIM and outsider behavior. Implications for bullying prevention efforts are discussed.