This study addressed school-contextual features of social disorder in relation to sixth-grade students experiences of bullying victimization and mental health complaints. It investigated, firstly, whether the schools concentrations of behavioural problems were associated with individual students likelihood of being bullied, and secondly, whether the schools concentrations of behavioural problems and bullying victimization predicted students emotional and psychosomatic health complaints. The data were derived from the Swedish National Survey of Mental Health among Children and Young People, carried out among sixth-grade students (approximately 12-13 years old) in Sweden in 2009. The analyses were based on information from 59,510 students distributed across 1999 schools. The statistical method used was multilevel modelling. While students own behavioural problems were associated with an elevated risk of being bullied, attending a school with a higher concentration of students with behavioural problems also increased the likelihood of being bullied. Attending a school with higher levels of bullying victimization and behavioural problems predicted more emotional and psychosomatic complaints, even when adjusting for their individual level analogues. The findings indicate that school-level features of social disorder influence bullying victimization and mental health complaints among students.