Growing numbers of researchers are using mixed methods to study migration, often highlighting the practical reasons connected with policy engagement. However, in this article we emphasize epistemological and theoretical rather than purely practical reasons for using mixed methods in the study of migration. Specifically, we argue that mixed methods designs are well suited to research that attempts to explain sociopolitical action within a post-positivist epistemological framework. We provide an example of this approach in the Diaspora Engagement Policies Project, a 5-year project to explain the global proliferation of formal government institutions for emigrants and their descendants.