Bullying is one of the most challenging issues facing students and schools worldwide. The disastrous consequences for victims and offenders are experienced daily by teachers and students and documented by numerous studies. The demand for evidence-based practice (EBP) in schools' anti-bullying work has increased in the last decade, consequently evoking considerable debate. Traditionally, evaluations of EBP and evidence-based preventive programs have addressed the impact on outcomes that are measured according to a hierarchy of evidence. The question of "What works?" is only one question among many that are relevant to policy makers and practitioners. The author suggests broadening the approaches to evaluation by developing a knowledge base grounded in research methods and strategies that give voice to the participants as well as provide sound empirical evidence of causal relationships. Research on anti-bullying interventions provides insight into the debate surrounding EBP in general.