Diaspora migration is one of many types of migration likely to increase considerably during the early twenty-first century. This article addresses the many ambiguities that surround diaspora migration with a view to developing a meaningful theoretical scheme in which to better understand the processes involved. The term diaspora has acquired a broad semantic domain. It now encompasses a motley array of groups such as political refugees, alien residents, guest workers, immigrants, expellees, ethnic and racial minorities, and overseas communities. It is used increasingly by displaced persons who feel, maintain, invent or revive a connection with a prior home. Concepts of diaspora include a history of dispersal, myths/memories of the homeland, alienation in the host country, desire for eventual return – which can be ambivalent, eschatological or utopian – ongoing support of the homeland and, a collective identity defined by the above relationship. This article considers four central issues: How does diaspora theory link into other theoretical issues? How is diaspora migration different from other types of migration? Who are the relevant actors and what are their roles? What are the social and political functions of diaspora? On the basis of this analysis a theoretical paradigm of diasporas is presented to enable scholars to move beyond descriptive research by identifying different types of diasporas and the dynamics that differentiate among them. Use of the proposed typology – especially in comparative research of different diasporas – makes it possible to focus on structural differences and similarities that could be critical to the social processes involved.