This article explores the contribution of Jürgen Habermas' discourse theory of morality, politics, and law to theorizing educational justice. First, it analyzes Christopher Martin's discourse-ethical argument that the development of citizens' discursive agency is required on epistemic grounds. The article criticizes this argument and claims that the moral importance of developing discursive agency should be justified instead on the basis of moral grounds. Second, the article examines Harvey Siegel's critique of Habermas' moral epistemology and suggests that Siegel neglects that the epistemic justification of moral claims proceeds differently from the epistemic justification of assertoric claims. Finally, the article presents a discourse-theoretic conception of educational justice that defends the importance of discursively justifying norms of educational justice through properly arranged structures of justification.