BackgroundTrauma affected youth in northwest Nigeria's humanitarian crisis face trauma exposure and limited mental health care; this study evaluated outcomes of a task-shifted, community delivered intervention.MethodsA convergent parallel mixed-methods, quasi-experimental design was employed. Participants (N=412, aged 15–24) were allocated to intervention (n=206) receiving a culturally adapted 10-session group Trauma-Focused Cognitive Behavioural Therapy (CBT) delivered by trained community lay providers, or to the waitlist control (n=206). Primary outcomes were posttraumatic stress disorder (PTSD) symptoms (Child PTSD Symptom Scale [CPSS]) and functional impairment (WHO Disability Assessment Schedule for Children). Assessments occurred at baseline, post-intervention, and 3 month follow up. Analysis used intention to treat three level linear mixed models accounting for clustering within communities. Qualitative methods involved 24 key informant interviews analysed using thematic analysis following COREQ guidelines.ResultsAt post-intervention, the intervention group showed significantly greater reductions in CPSS (mean difference: -8.3, 95% CI: -10.6 to -6.0, p<0.001, d=1.35) and WHODAS-Child scores (mean difference: -8.9, 95% CI: -11.5 to -6.3, p<0.001, d=1.40) compared to controls. Gains were maintained at follow-up. Qualitative themes highlighted the necessity of health system integration and community ownership for sustainability.ConclusionA task-shifted, community-delivered trauma-focused intervention demonstrates promising effectiveness in reducing PTSD symptoms and improving functioning among youth in northwest Nigeria, indicating potential for scale-up pending confirmatory evidence from randomised controlled trials and health system integration.Rwanda J Med Health Sci 2026;9(2):342-355