School-based mental health programmes have been implemented in various regions to address behavioural issues among primary school students. However, their effectiveness varies across different cultural contexts and settings. The study employed qualitative research methods including participant observation, semi-structured interviews with teachers and students, and document analysis of programme materials. Data were collected from multiple primary schools across Tanzania over a year. Findings suggest that while some programmes showed positive changes in student behaviour, others encountered challenges related to resource allocation and cultural adaptation. The ethnographic approach highlighted the need for culturally sensitive implementation strategies and continuous evaluation of mental health interventions within primary school settings. Educators should prioritise training on cultural competency and consider local resources when implementing mental health programmes. Schools could benefit from periodic reviews to adapt programmes as needed. primary education, behavioural outcomes, mental health, ethnography, Tanzanian schools