This study aims to investigate the prevalence of emotional and behavioural problems in unaccompanied refugee children and adolescents living in Belgium. A total of 166 unaccompanied refugee children and adolescents, living in different large- and small-scale centres, in foster care or alone, participated in the study. Between 37 and 47% of the unaccompanied refugee youths have severe or very severe symptoms of anxiety, depression and post-traumatic stress. Girls and those having experienced many traumatic events are at even higher risk for the development of these emotional problems. Social workers also report a high prevalence of internalising problems in this population and they also report important externalising problems in unaccompanied refugee youths. Being unaccompanied is an important risk factor for the emotional wellbeing of refugee children and adolescents. Therefore, appropriate measures on reception and care should be taken in order to support these youths.