Global conflict in 2019 created record numbers of displaced children. These children have experienced multiple traumas and subsequently suffer high levels of mental health symptoms. Cognitive-behavioural therapy (CBT) is commonly used for post-traumatic stress disorder (PTSD), depression and anxiety, however the current evidence-base of CBT in child refugees is sparse, with mixed results. This study aimed to assess the effects of CBT on symptoms of PTSD, depression and anxiety in child refugees/AS. Ethics were reviewed and granted by the University of Manchester ethics committee. Medline, Embase, Cochrane, PsycINFO and CINAHL were systematically searched. Studies were included if CBT was delivered to refugee/AS children with pre and post-intervention measures of symptoms. Sixteen studies fulfilled criteria. In all studies, mental health symptom scores post-intervention had reduced, suggesting an improvement in mental health following CBT. This reduction was statistically significant in twelve studies (p < 0.001-0.5), clinically significant in eight studies and maintained at follow-up periods. No adverse effects of CBT were identified. This is the first systematic review to focus solely on CBT in child refugee populations, with unanimously positive results. Its use is cautiously recommended, however the need for more methodologically rigorous studies in this population is highlighted.