This article presents elements of a capability perspective on impairment and disability and develops in connection with it a multidimensional and relational account of disability. It suggests how a capability perspective provides new and fundamental insights into the conceptualization of impairment and disability, and in doing this, resolves the tension between natural and social causal factors evident in current discussions of disability and education. It argues that the capability approach is innovative with respect to the centrality of human diversity in assessing equality, and that the specific understanding of human diversity proposed, the democratic decisional process promoted and the normative account of disability those entail, all have the potential to take educational theory and inclusive education policies in fruitful directions. (Contains 6 notes.)