Under which conditions, if any, is it morally permissible for states to grant non-citizen residents (‘denizens’) different political, socio-economic, and cultural rights than citizens? What, if anything, could justify legal rights-differentiations along the lines of citizenship? This special issue scrutinizes these politically increasingly salient questions from a wide range of perspectives, drawing on recent literature in the ethics of migration, citizenship, multiculturalism, and refuge, as well as on normative theories of law, territory, and settler colonialism. In this introduction to the (...) volume, I sketch a conceptual map of the emerging debate on justice for denizens, making explicit some underlying theoretical assumptions common to each of the three key domains of legal rights-differentiations (political, socio-economic, and cultural rights). I distinguish the question of what is owed to denizens as a matter of justice, from that of what justice permits and requires in respect to denizens generally. And I outline four models, implicit in the literature, for theorizing the moral rights different types of denizens have and lack – to help determine which forms of unequal treatment wrong them. I conclude by providing brief summaries of the seven contributing articles, pinpointing them on my conceptual map. (shrink)