Diasporas are dispersed migrant populations that retain a shared group identity and orientation towards a distant homeland. Increasingly, states are reaching out to their diasporas. They do so in various ways, often coordinated by formal diaspora institutions. In the process, states are reconfiguring what national membership means. How do different conceptions of national membership drive and shape whether and how states â€˜engage the diasporaâ€™? Using a mixed methods research design based on original qualitative and quantitative data, this paper examines how three different conceptions of national membership â€“ economic, ethnic, and civic â€“ shape the emergence of formal governmental diaspora institutions in migrantsâ€™ states of origin. First, it describes the complex relationship between concepts of national membership and the emergence of diaspora institutions, through two qualitative case studies. Next, the paper employs multinomial logistic regression to systematically examine the relationship between measures of national membership conceptions and measures of diaspora institution establishment, across 181 states. The central finding is that, contrary to conventional wisdom, it is not only economic conceptions of national membership that drive states to engage the diaspora, but also ethnic and civic membership conceptions. This finding suggests the drivers of diaspora policies are more complex and nuanced than is currently understood, and can inform future enquiry on conceptions of national membership and state diaspora engagement policies.