For most of the 20th century, citizenship was an exclusive relationship between a nation-state and the individuals in its territory. In recent decades, however, an increasing number of states moved to permit dual citizenship and offer rights to non-residents. As a consequence, millions of people in Eastern Europe, Latin America and the Middle East have managed to secure non-resident dual citizenship from European Union countries, which they use to facilitate migration, travel with greater ease or just keep as an “insurance policy”. The proliferation of Hungarian citizenship in Serbia is part of this global phenomenon. Since 2011, Hungary allows the “reacquisition” of citizenship by applicants whose ancestors lived within the country’s pre-1920 borders, if they can demonstrate their knowledge of Hungarian. The response in Serbia was dramatic: in just under four years, 120,000 people – 1.5% of Serbia’s population – acquired citizenship. Demand is not restricted to ethnic Hungarians, and large numbers of ethnic Serbs have begun to study Hungarian with the aim of securing EU citizenship. In this paper, I use material from 60 interviews and demographic statistics to explore the case of Hungarian-Serbian dual citizenship. I focus on the unintended consequences that unfold when individuals respond strategically to the opportunities created by state policies, paying particular attention to the effects on ethnic relations, emigration and the emergence of “markets for citizenship”.Yossi Harpaz is a Ph.D. student in sociology at Princeton University. He holds an M.A. in Sociology and Anthropology from Tel-Aviv University. Yossi’s research interests include citizenship, nationalism, migration, globalization and comparative-historical sociology. His dissertation project compares formations of dual citizenship in Serbia, Mexico and Israel. His work was published in International Migration Review and other journals.