The concept of transnationalism, despite a variety of earlier uses, has recently been used to describe the sociological phenomenon of cross-border migrants considering more than one place ‘home’. This can be in terms of identity and belonging, cultural expression, family and other social ties, visits, financial flows, organising working life in more than one nation-state or transnational political projects. In this paper I discuss the theory and practice of transnationalism to assess the practical, explanatory and normative strength of the concept. (...) I then introduce three different forms of cosmopolitan approaches and assess whether transnational migrants' practices contribute to a cosmopolitan outlook and active global citizenship. I show that the extent to which transnationalism contributes to various forms of global citizenship varies according to the different conceptualisations of transnationalism and cosmopolitanism. In conclusion I draw out the implications of these differences for the future protection of the rights of migrants. (shrink)