ObjectiveChildren and young people (CYP) from low-and-middle-income and developing countries are at risk of poor mental health and wellbeing. Yet these regions are generally under-resourced in terms of mental health services. As a first step to inform service planning and delivery in the English-speaking Caribbean we pooled the available evidence to estimate the prevalence of common mental health problems.MethodsA comprehensive search of CINAHL, Cochrane Library, EMBASE, MEDLINE, PsycINFO, LILACS, and Web of Science databases, supplemented by grey literature searches was performed until January 2022. Studies conducted in the English-speaking Caribbean that reported prevalence estimates of mental health symptomology or diagnoses in CYP were included. The Freeman-Tukey transformation was applied to calculate the weighted summary prevalence under a random-effects model. Subgroup analyses were also performed to observe emerging patterns in the data. Studies were quality assessed using the Joanna Briggs Institute Prevalence Critical Appraisal Checklist and the GRADE approach. The study protocol was registered with PROSPERO, CRD42021283161.Results33 publications from 28 studies representing 65,034 adolescents from 14 countries met the eligibility criteria. Prevalence estimates ranged from 0.8 to 71.9% with most subgroup estimates between 20 and 30%. The overall pooled prevalence of mental health problems was 23.5% (95% CI 0.175–0.302; I2= 99.7%). There was limited evidence of significant variation in prevalence estimates among subgroups. The quality of the body of evidence was judged as moderate.ConclusionIt is estimated that between 1 in 4 and 1 in 5 adolescents in the English-speaking Caribbean experience symptoms of mental health problems. These findings highlight the importance of sensitisation, screening, and provision of appropriate services. Ongoing research identifying risk factors and validating outcome measures is also needed to inform evidence-based practice.Supplementary InformationThe online version contains supplementary material available at 10.1007/s44192-023-00037-2.