The paper sets out a theoretical approach for understanding the quality of education in low income countries from a social justice perspective. The paper outlines and critiques the two dominant approaches that currently frame the debate about education quality, namely, the human capital and human rights approaches. Drawing principally on the ideas of Nancy Fraser and Amyarta Sen the paper then sets out an alternative approach based on a theory of social justice and of capabilities. The paper develops an overall understanding of how education quality can be understood in relation to the extent to which it fosters key capabilities that individuals, communities and society in general have reason to value. It then analyses three inter-related dimensions of the quality of education from a social justice perspective. Each dimension is considered in relation to contemporary policy debates and research including the work of EdQual. The first dimension, that of inclusion draws attention to the access of different groups of learners to quality inputs that facilitate the development of their capabilities, the cultural and institutional barriers that impact on the learning of different groups and priorities for overcoming these. The second dimension, that of relevance, is concerned with the extent to which the outcomes of education are meaningful for all learners, valued by their communities and consistent with national development priorities in a changing global context, whilst the third dimension, that of democracy considers how decisions about education quality are governed and the nature of participation in debates at the local, national and global levels. It is argued that a social justice framework can provide an alternative rationale for a policy emphasis on quality that encompasses but goes beyond that provided by human capital and rights approaches; that through emphasising the importance of context and through providing a normative basis for thinking about quality in relation to development, it provides a useful starting point for re-conceptualising education quality and how it can be evaluated; and, that it draws attention to the central importance of public dialogue and debate at the local, national and global levels about the nature of a quality education and quality frameworks at these levels.