Teachers respond differently to the misbehavior of ethnic minority students as compared with that of ethnic majority students. This finding can be traced back to teachers' stereotype-driven cognitions and behavior. Moreover, preservice teachers have been shown to apply harsher interventions in response to student misbehavior than inservice teachers. In a quasi-experimental study, we found that inservice teachers' responses were less severe than preservice teachers' responses to student misbehavior. Even more interesting, preservice teachers' interventions were ethnically biased, whereas inservice teachers' interventions did not differ by students' ethnic origins. The findings are discussed with respect to consequences for teacher education.