Kant's unduly neglected concept of cosmopolitan law suggests a third sphere of public law -- in addition to constitutional law and international law -- in which both states and individuals have rights, and where individuals have these rights as ‛citizens of the earth' rather than as citizens of particular states. I critically examine Kant's view of cosmopolitan law, discussing its addressees, content, justification, and institutionalization. I argue that Kant's conception of ‛world citizenship' is neither merely metaphorical nor dependent on an (...) ideal of a world-government. Kant's views are particularly relevant in light of recent shifts in international law, shifts that lead away from the view that individuals can only be subjects of international law insofar as they are citizens of particular states. Thereby, a category of rights has emerged that comes close to what Kant understands by cosmopolitan law. (shrink)