This paper explores the potential of Bronfenbrenner’s Bio-ecological Model of Human Development (Bronfenbrenner and Morris, 2006) as a framework for theory and research in education. It draws on other well-known conceptual approaches, particularly Bourdieu’s theories of social reproduction, habitus, field and cultural capital, investigating points of theoretical enhancement and synthesis. This culminates in the development of eight Propositions for a Bio-ecological Framework which are then tested using data from a qualitative examination of two key educational transitions, pre-school to primary and primary to secondary school. Using qualitative methodologies, this research explores perspectives of children, teachers and parents in a case-study primary school in Ireland, the three pre-schools that feed into it, and the two secondary schools into which it feeds. The data yield the key finding that relationships are crucial to positive transitions, perhaps even more important than the contexts in which they take place. Other findings emphasise the impact of diversity (cultural, socio-economic, etc), specific skills for traversing new settings, the importance of time, both personal and socio-historical, and the vital nature of supports for transition, locally and at policy-level. The Propositions of the Bio-ecological Framework are supported by the data indicating that it provides an appropriate conceptual basis for future work. The paper concludes with recommendations for policy, research and practice.