The Ministry of Education is endeavouring to build an education system that is responsive to the challenges of the 21st century. This includes revising the school curriculum and a major investment in programmes of research and development. This paper examines the discourses relating to diversity and education that have become embedded in the very foundations of national education policy and subsequent practice. These are often assumed to be unproblematic and go uncontested, but this paper identifies a (dis)array of ideas and understandings, and argues that these arise from a lack of conceptual clarity. This has implications for decision making by implementers of policy, which can serve to restrict (rather than enhance) their efforts to improve the effectiveness of teaching and learning, particularly for groups of learners the education system has under-served.