In the present study, we examine the personal belief in a just world (PBJW) for teachers and learners in predominantly Afrikaans-speaking South African schools, and the relationship between teachers' PBJW and their perception of problem behaviour in the classroom. The study is informed by national debates of school violence in South African schools, and international debates on zero-tolerance policies to address school violence. Our findings suggest that teachers' PBJW predicts their perception of problem behaviour in classroom behaviour in four areas, namely challenging authority, disrespecting rules and authority and teacher negativity. Teachers with a strong PBJW were more likely to view classroom behaviours as problematic. Children generally reported that their teachers were fair and just and liked them. However, boys were more likely to have experienced trouble with their teachers and to view them as unfair and unjust. We discuss the significance of the findings in terms of school violence and also mention gendered interpretations to school violence.