In this article, we argue that transnational citizens – those international migrants who maintain connections to their country of origin and its diaspora – can be moderate cosmopolitans. We hold the primarily normative idea of cosmopolitanism up against the empirical literature on transnationalism, and show how cosmopolitanism can develop from the migration process itself and the subsequent connection to a diversity of places. We claim that studying migrants who lead transnational lives can increase our knowledge about the compatibility of attachments to particular places or people on the one hand, and cosmopolitan outlooks on the other. It can also correct the narrow focus in European politics as well as in migration studies on ethnic or national values and identities, encouraging a more intersectional approach. We thus aim to contribute to a reconceptualisation of the relationships between polity, territory and civic responsibility in culturally and religiously diverse societies in Europe today.