This paper examines the way the metaphor of diversity provides a moral basis for inequality in Singapore's meritocratic education system. Based upon a collection of policy texts from 2002 to 2012, our analysis illustrates that the metaphor of diversity in policy texts provides ways for systemic discrimination within the education system and that this inequality is given legitimacy as necessary through various moral discourses. The paper employs a critical discourse analysis that draws upon the relationship between language analysis, the philosophical study of valuation, and political economy as a composite formulation of values to highlight the ways in which an argument for inequality permeates policy from within a frame of meritocracy, and to analyse how changes associated with new modes of value determination serve to legitimize inequality.