Young people spend nearly half of their waking hours at school, and this complex context has the potential to support or undermine children’s development. A new initiative in Aotearoa New Zealand called E Tū Tāngata (ETT; Stand Together) is being implemented in a variety of schools to help address the concerning rates of young people experiencing mental health difficulties and the cultural practice of tall poppy syndrome, in addition to promoting students’ sense of belonging to their school, self-worth, and positive relationships with peers and school staff. ETT promotes three key mindsets – You Have Value, We Succeed Together, and Others Matter. In this retrospective, qualitative evaluation of ETT at a single target school, six students new to the school participated in semi-structured interviews exploring their recent school transition, their experience of this new school climate, sense of school belonging, and relationships with peers and teachers. Across all participants, their school transition experience was consistently described in the context of peer relationships, rather than other elements of school climate. Five participants reflected positively about their school transition, the positive and socially inclusive climate at the target school, and sense of school belonging; whereas the sixth participant’s experience of peer exclusion and difficulty adjusting to the target school provided a sharp contrast. These new students had difficulty in distinguishing between the ETT mindsets and the school values, which may be due to insufficient exposure or could also reflect issues with implementation. The findings were broadly consistent with the literature on school transitions, school climate and belonging, and are generally supportive of the ETT theory of change model. In light of the strengths and limitations of this study, additional opportunities to further examine the hypotheses of the ETT theory of change in future research are discussed.