This paper addresses the question of when and why duties are conditional on compliance on the part of others, by examining the role of reciprocity in Rawls's theory of justice. In particular, it argues that the idea of reciprocity and the relational nature of distributive justice can help explain three otherwise puzzling aspects of Rawls's view: (1) his claim that justice has to be "congruent" with the good; (2) his claim that the justification of a political conception of justice depends (...) on showing that an overlapping consensus of reasonable comprehenisve doctrines is possible, even after the freestanding argument for the political conception has been successfully completed; (3) his claim that there are no global duties of distributive justice, beyond the non-comparative duties of aid and reparation. Each of these arguments has been the subject of controversy partly because of a lack of attention to reciprocity, the paper argues, and the relational nature of Rawls's non-luck-egalitarian position. (shrink)