This paper offers a theoretical exploration of the impact of diversity in schools on attitudes to inequality in students' later life. Reflecting on recent changes on the school system in England, and building on work on how values are formed and how inequalities between groups may be either perpetuated or changed, it seeks to investigate the development of values and agency goals relating to the reduction of poverty and inequalities, particularly between groups. School education has the potential to foster civic participation and moral values, and formal schooling can be seen as a unique site for the development of such values at a formative period of individual development, through processes such as collective reasoning and encounters with difference and inequality. While these issues have been explored with regards to educational content, most notably through citizenship education, it is equally important to consider the social context within which formal learning takes place, particularly the diversity of the school body itself, and how this is managed. This paper draws on existing literature on education, values and school diversity to examine how the capability approach can provide insight on the development of social justice values through education.