This paper explores the understandings three young children have of the behaviour 'crisis' besetting our schools. Specifically, this paper examines semi-structured interview talk with three boys aged between six and eight years of age who were labelled by medical specialists as exhibiting Attention Deficit Hyperactivity Disorder (ADHD)1, that is, behaviour that is considered to be 'inappropriate'. The purpose of this paper is to report the boys' mis/understandings of the origins, management and outcomes of inappropriate behaviour. The findings reveal five core mis/understandings about inappropriate behaviour: it is a disease; medication is the most appropriate form of management; it affects their intellectual functioning; it should be kept secret; and those with inappropriate behaviour will be excluded from school-based social networks. In conclusion, this paper considers possible consequences for the boys' mis/understandings and implores those working with such labelled students to assist them in better understanding the origins, treatment and outcomes of labels and dealing with the outcomes of their socially constructed identities.