A diverse range of high school students dominate negative outcome data in Aotearoa-New Zealand, and a shift in how we support them is needed for outcomes to improve. Following PRISMA guidelines, a systematic review of published and grey literature was carried out to identify how research shows belongingness is an important element in improving outcomes for this population. Eight qualitative studies which explored the subjective experience of belonging for diverse students in high school education were identified and reviewed. The review highlights the paucity of research in Aotearoa-New Zealand, which privileges the voices of young people and focuses on their experiences of belonging, or not-belonging, in high school. The results identified four overarching themes: a sense of belonging is a protective factor, teachers are pivotal in creating a sense of belonging, safe spaces are needed to belong, and schools experienced as unsafe spaces. This study provides school staff with a window into the lived experiences of diverse students and links contemporary education policies with belongingness research. The findings of this review have important implications concerning the health and wellbeing of our young people in Aotearoa-New Zealand, and highlight belonging as a fundamental component in improving outcomes for diverse students.