Purpose: Immigrant youth face both unique and disproportionate barriers to sexual health. Targeted sexual health education to redress these disparities requires creative and inclusive approaches that consider personal and community challenges and strengths. This study piloted a novel intervention: SExT: Sex Education by Theatre, a theatre-based, culturally-relevant, participatory action research programme delivered in an immigration destination neighbourhood in Toronto, Canada. Design/methodology/approach: Nineteen youth were trained as peer educators. They participated in theatre-based workshops on sexual health topics which culminated in a performance for local peers. Mixed methods evaluation included surveys which investigated changes in personal and social development over three time-points (pre, post, 4-month follow-up). The impact of the intervention on peer educators was explored in greater depth using qualitative peer interviews and focus groups. Findings: Quantitative study findings indicated that peer educators experienced significant improvements in personal growth, social inclusion and social engagement after participating in SExT and these improvements were maintained at follow-up. Thematic qualitative analysis further indicates that meaningful involvement in a sex education theatre intervention may protect against adverse outcomes and promote self-actualization, connection and active citizenship. Originality/value: This research stands out for its innovative approach to addressing sexual health disparities among immigrant youth in Toronto using culturally relevant theatre-based peer education. SExT may serve as a model for sexual health interventions for newcomer youth and other priority groups in diverse contexts.