This article explores the social theory and consequent methodology that underpins studies of transnational migration. First, we propose a social field approach to the study of migration and distinguish between ways of being and ways of belonging in that field. Second, we argue that assimilation and enduring transnational ties are neither incompatible nor binary opposites. Third, we highlight social processes and institutions that are routinely obscured by traditional migration scholarship but that become clear when we use a transnational lens. Finally, we locate our approach to migration research within a larger intellectual project, taken up by scholars of transnational processes in many fields, to rethink and reformulate the concept of society such that it is no longer automatically equated with the boundaries of a single nation-state.