The construction of theories about migration has long been the goal of scholars from the disciplines of economics, demography, and sociology. Theories aimed at explaining ‘why the phenomena of international migration occur,’ ‘why individuals make the choice of migrating,’ and ‘why the flows of migration fluctuate the way they do’ have tremendously improved our understanding of migration. The political and policy aspects of international migration, however, had largely been neglected until political scientists turned their attention to migration studies more recently. The questions political scientists are interested in include ‘if and how migration policies affect the flow of migration’ and ‘what factors contribute to migration policy output.’ Against the background of the recent call to ‘bring the state back in’ in migration studies, this article delineates the development of migration studies within different disciplines and assesses the contributions by political scientists in the construction of migration theories.