The benefits of belonging and feeling connected to school for adolescent mental health and wellbeing are well documented, but how belonging is fostered is less understood. The present article puts forward a new conceptual framework of school belonging based on Bronfenbrenner's (1979) sociological model of human development, using evidence from a range of previous peer-reviewed studies to better understand the factors that occur across five levels that affect a students' sense of school belonging (i.e., the individual level, the microsystem, the mesosystem, the exosystem, and the macrosystem). The conceptual framework is used to present a range of evidence-based school belonging strategies (some with examples) that schools can use to enhance student belonging. This article makes an original contribution to the field of psychological and educational research by presenting a socio-ecological framework to explore the themes that influence school belonging within a secondary school system. It broadens the frame of reference of school belonging beyond the individual student to consider features of the broader school system and environment.