This study examines the interplay between individual characteristics (social status, provictim attitudes, and family messages about conflict resolution) and classroom descriptive and injunctive norms (peer victimization behaviors and bullying-related beliefs, respectively) in explaining defending behavior. For this purpose, we used a representative sample of 2,050 Spanish primary school children (50.80% girls) from grades 3-6 (M = 9.80 years; SD = 1.24), nested within 103 classrooms in 27 schools. Multilevel modeling analyses showed that both individual and class characteristics helped to explain defending behavior. In addition, random slopes revealed that children with a high social status were more likely to support victims in classrooms where bullying was less accepted. These results expand previous findings in this field, demonstrating the need for a multilevel and interactive approach to the study of defending behavior.