By placing emphasis on equity and social mobility, the current UK education policy for England focuses on narrowing the educational attainment gap between more and less advantaged groups of young people--an approach that has strong parallels in many other Anglophone countries around the world. We argue that these policy and associated practice proscriptions tend to privilege an individualised narrative of agency for young people, teachers and schools more generally. Our paper argues that this individualised approach is highly problematic in that it decontextualises the complex and real agentic work of young people in schooling, making it difficult to empirically and theoretically account for differences in educational outcome between and within groups of young people. Informed by a social realist perspective, and in particular the work of Margaret Archer, we propose a theoretical model that we suggest provides greater explanatory and predictive power. The model focuses on the way ecologies of development emerge for young people. We suggest that such ecologies reflect different structural and cultural factors and processes, combining in ways that enable and/or constrain young people's educational reflexivity and agency and their ensuing educational engagement and attainments. We believe that building a typology of such ecologies of educational reflexivity and agency provides improved ways of developing equitable educational policies and practice--ones that relate clearly to the compositional mix of young people in schools and enable the development of interventions that better relate to such ecologies.