Although the Horn of Africa was historically one of the earliest destinations for Yemeni migrants, it has been overlooked by scholars, who have otherwise meticulously documented the Yemeni presence in the Indian Ocean region. Subjects of Empires/Citizens of States draws on rich ethnographic and historical research to examine the interaction of the Yemeni diaspora with states and empires in Djibouti and Ethiopia from the early twentieth century, when European powers began to colonize the region. In doing so, it aims to counter a dominant perspective in Indian Ocean studies that regards migrants across the region as by-products of personal networks and local oceanic systems, which according to most scholarship led to cosmopolitan spaces and hybrid cultures. Samson Bezabeh argues that far from being free from the restrictions of state and empire, these migrant communities were constrained, and their agency structured, by their interactions with the institutions and relations of states and empires in the region. Elegantly combining theoretical readings with extensive empirical findings, this study documents a largely forgotten period in the history of Yemeni migration as well as contributing to the wider debates on class, citizenship, and ethnicity in relation to diaspora groups. It will appeal to specialists in Middle East studies and to those who study the Indian Ocean and Horn of Africa regions, as well as to migration and diaspora studies scholars, nongovernmental organizations, and policy makers concerned with the Red Sea and Gulf of Aden region.