Within categories of special educational needs, emotional and behavioural difficulties have received much attention in recent years, particularly in relation to their definition and identification by parents and teachers. This paper stems from previous research which highlights how children from disadvantaged backgrounds and those attending schools designated as socio-economically disadvantaged are significantly more likely than their peers to be identified as having a special educational need of a non-normative type such as emotional behavioural difficulty (EBD). Using data from the Growing Up in Ireland study, it examines whether the EBD identified by teachers or within certain schools is matched by the child's own performance on an internationally validated emotional and mental health measure--the Piers-Harris. Findings show that overall self-reported social emotional well-being bears a strong relationship to the probability of being identified with an EBD. However, boys, children from economically inactive and one-parent households and children attending the most disadvantaged school contexts are more likely to be identified with having an EBD, even after taking into account their social background characteristics and their scoring on the Piers-Harris measure. These findings suggest that the subjective nature of EBD identification is resulting in a disproportionate number of these children being identified with EBD. The implications of this study are explored for existing disability/SEN classification systems, school-wide intervention models and the impact on individual students labelled as EBD. Overall, the findings pose searching questions about the validity of employing SEN classification systems in deciding eligibility and types of appropriate provision. (Contains 2 tables and 1 figure.)