Previous studies have highlighted a high level of language impairment (LI) and pragmatic language disorder (PLD) amongst children with social, emotional and behavioural difficulties (SEBD). However, little is known regarding the impact of LI in the severity of PLD in this group. This study investigates the language and pragmatic language skills of a group of boys with externalising behaviour (EB), making comparisons with a control group matched for age and socio-economic status. Specifically, the study asks whether there is a difference in pragmatic language presentation between those with and without significant LI. In this study, 35 boys aged between 7 and 12 years identified at high risk of an EB diagnosis and 42 controls participated in assessment of structural and pragmatic language skills. Comparisons were made between these two groups and then within the EB group between those with and without LI. The EB and Control groups were well matched for age and SES but the EB group scored significantly lower than the Control group in measures of language and pragmatic language. Within the EB group the presence of LI was not found to differentiate participants with regard to teacher rating of pragmatic language skills. Furthermore, despite considerable differences in structural language skills within the EB group, teachers rated all participants with EB very similarly in this area. This raises questions about their functional communication skills and teacher perception of these pupils which are discussed along with implications for practice.