This chapter describes a school-based intervention program designed to tackle bullying in school classes. In contrast to previous prevention programs, Viennese Social Competence (ViSC) training provides students with systematic theoretically based guidance in becoming responsible and competent actors in conflict situations. ViSC training has been especially designed for disadvantaged adolescents aged fifteen to nineteen who are considered at risk for eventual problems. This population has rarely been the target group of prevention programs. Until now in Austria, prevention programs have mostly been conducted in privileged schools like Gymnasiums (college prep) and not in schools with predominantly disadvantaged students (see also Atria & Spiel, 2003). Furthermore, these programs mostly target students below fifteen years of age. Thus a program like ViSC training might well be the last opportunity for youths to work on their social behavior, for example, to learn how to adequately deal with conflicts, before they have to manage their lives as adults in work or family.