Disturbing, problematic, or challenging student behaviour is said to be among the greatest challenges facing today's school life. However, despite the apparent commonsensical nature of the issue, there is no commonly agreed upon definition for such events, and there is often very thin analysis of what actually becomes disturbed, challenged, or problematised in such instances. In this article, disturbing behaviour is seen as a discursive practice that produces reality; it is a historically and socioculturally formed coming-together of various intersecting power-related discourses that make claims about individuals and contexts. Informed by post-structural approaches, this theoretical article looks at how ideas of disturbing behaviour come to be formed within the discursive environment of school. The article argues that behind the idea of disturbing behaviour are the ideas of a normal developmental course and an idealised student, as well as increasing emphasis on management and measurement in school.