Abstract
BACKGROUND: Internationally, adolescent engagement in risky sexual behaviours (RSB) remains a global health problem. Comprehensive sexuality education (CSE) is an effective strategy for enhancing positive adolescents’ sexual and reproductive health (SRH) outcomes. Effective adolescent engagement with CSE in schools can improve academic and SRH outcomes. We conducted this study to explore adolescent engagement with CSE and the factors that support and hinder this engagement in schools. METHODS: This descriptive qualitative study was conducted among 52 purposefully selected participants, comprising 17 teachers teaching CSE and 35 grade 12 students in nine secondary schools across Kitwe district. Data were collected through focus group discussions (FGDs) and in-depth interviews (IDIs). A six-step thematic analysis, supported by NVivo software (NVivo.x64), was employed. Themes were organised and arranged within the Bundick conceptual model of youth engagement. Data collection continued until the saturation point was reached. RESULTS: Five themes emerged regarding the engagement among teachers, students and the CSE content. Student engagement with CSE was related to trust and confidence in their teachers, the perceived relevance and distinctiveness of the CSE content, students’ recounts of negative sexual experiences, the subjective assessment of CSE, and the informal and practical delivery of CSE lessons. The factors that influenced student engagement with CSE include poor-quality teacher-student relationships, a lack of teacher skills and competencies, and insufficient time allocation to implement participatory methods. Facilitators of student engagement were related to the supportive school environment, the perceived distinctiveness of CSE, and the perceived relevance of CSE as a key source of accurate SRH information. CONCLUSION: The study highlights that students’ engagement with CSE is shaped by pedagogical quality, teacher competence, relational trust, and the perceived relevance of subject content to students’ SRH experiences. It demonstrates that effective engagement with CSE extends beyond content delivery to encompass supportive teacher-student relationships, participatory pedagogical approaches, and school environments that prioritise students’ psychological wellbeing and voice. The study further underscores the importance of strengthening pre-service and in-service teacher training and situating CSE within a whole-school context that includes parental engagement. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-026-26607-x.