Urban West African settlements face significant mental health challenges among adolescents, particularly related to depression and anxiety. A systematic literature review was conducted using databases such as PubMed and Web of Science, focusing on studies published between and . Studies were selected based on predefined inclusion criteria related to the effectiveness of school-based mental health programmes in reducing depression and anxiety rates among urban West African adolescents. Findings indicate a moderate reduction (pooled effect size = -0.45, CI [-0.61, -0.29]) in depression and anxiety symptoms following one year of intervention compared to control groups. School-based mental health support programmes show promise for reducing depressive and anxious symptoms among urban West African adolescents but require further robust evaluation and tailored implementation strategies. Future research should focus on the development and testing of evidence-based, culturally adapted school-based mental health interventions in diverse urban settings to achieve sustainable reductions in adolescent mental health issues.