Since the 1980s in Sweden, children’s violent actions in schools have been reported to the police as criminal offences more frequently than before. This increasing trend is analysed against the background of a general increased cultural sensitivity to violence and slowly developing social changes that affect the propensity to report every form of violent incident to the police. This project analyses 1,239 police reports of assault, unlawful threat, molestation and insulting behaviour committed in schools by 7- to 14-year olds in ten municipalities in the Stockholm area. The time period studied is from 2000 to 2010. Regression analysis shows systematic differences among schools in different areas and social contexts. Average merit ratings, which are a measure of the educational quality of schools, explain most of the variance and correlate negatively with reported incidents. There are also significant differences among municipalities and school forms in terms of police reports. So-called resource schools, which are designed to serve children with special needs, report extremely high numbers of incidents per child. Reporting seems to have been routinised in many schools, including resource schools. Our results can be interpreted as suggesting that increased cultural sensitivity generates a bias against children in less affluent contexts.