The aim of this article is, in a chronological perspective, to identify, discuss and problematise concepts for children's 'problems' in compulsory school and the contexts in which they have been categorised and used. To clarify the categorisation in context, the article is based on a previous study on categorisation in Swedish youth education from a historical perspective. School health reports from the 1940s to the 1980s in this document study constituted the empirical data material on which the discussion in this article is based. An ecological model of analysis was used with the main analytical tools: concept use, curricula, documentation routines, experts and educational support measures. The various tools elucidate the context to which the categorisation may be related, and show that social, cultural, medical and psychological influences contributed to what were identified, observed and documented as children's 'problems' at school from the school health services' point of view. On the basis of the empirical study and the components pinpointed by the analytical tool, present-day terminology of children's 'problems' in Swedish schools today is discussed and problematised.