This paper examines the under-researched phenomenon of classroom exclusions and their implications for school exclusions. Responses from nearly 1500 secondary school pupils indicate that being expelled from the classroom is a common phenomenon. On average, one-third of pupils have been asked to leave the classroom at some point in the previous year. However, it is more common in some schools, and for some pupils, than others. Most often, excluded pupils stand in school corridors with nothing to do. Not only does classroom exclusion lead to a loss of learning time, it may mark the beginning of a trajectory towards school exclusion. Whether it takes on this more serious significance may depend on the extent to which the pupil perceives the teacher's action as appropriate and fair. The paper concludes that classroom exclusions are worthy of investigation not only for lost learning time but because of their significance for future school exclusion. However, in unravelling whether a classroom exclusion 'matters', it is important to examine not only the circumstances which led to it, but the pupil's perception of the legitimacy of the teacher's action.