The study examines whether school-level immigrant concentration is related to students' involvement in violence, and whether students' moral values moderate the relationship between immigrant concentration and violence. The study is based on six nationally representative school surveys conducted by the Swedish National Council for Crime Prevention between 1999 and 2011, with a combined sample of 38,711 adolescents. We have combined different surveys to create one large pooled data set to evaluate segregation effects at the school level. Multilevel linear probability models are used to examine cross-level interaction effects. This study shows that contextual effects impact students differently, and that the relationship between immigrant concentration and violence is considerably stronger for adolescents with weak personal moral values. The paper provides empirical support for the differential vulnerability hypothesis. Policy and practice would benefit from a focus on the further development of programs and interventions that target personal moral values, not least in schools.