The aim of the present study is to investigate schoolchildren's social representations on the causes of bullying. Individual qualitative interviews were conducted with 56 schoolchildren recruited from five elementary schools in Sweden. Mixed methods (grounded theory as well as descriptive statistic methods) were used to analyze data. According to the findings, the most prevalent social representation on bullying causes among the children is to view bullying as a reaction to deviance. The second most frequently used explanation type is to view bullying as social positioning. Other social representations on bullying causes are to explain bullying as the work of a disturbed bully, a revengeful action, an amusing game, social contamination, and a thoughtless happening. Social representations of bullying causes appear to be linked to the more general process of social categorization and seem in many bullying cases to promote moral disengagement among the children. © 2010 Wiley Periodicals, Inc.