This commentary reviews research findings of the five papers in the special entitled “School-related Factors in the Development of Bullying Perpetration and Victimization”, which represent critical areas that are often overlooked in the literature. First, one paper points to the complex interaction between a genetic disposition for aggression and classroom norms toward aggression. Second, an intervention paper unpacks the underlying mechanisms of an efficacious school-wide bully prevention program by opening the “black box” and testing for mediators. Third, the remaining studies employ a wide range of rigorous designs to identify how teachers’ attitudes, behaviors, and classroom practices play a critical role in the prevalence of victimization and bullying in the classroom. Further, teachers’ attitudes and behaviors are shown to be predictive of youth’s willingness to intervene to assist a peer who is being victimized. Results are situated in what is known about bullying prevention, and how the findings from these studies could maximize the sensitivity of future prevention efforts.