As the processes of globalization intensify, the issues of people migration and citizenship receive more scholarly attention than ever. The questions regarding dual or even multiple citizenship are unavoidable nowadays and governments have to decide whether they tolerate the fact that their citizens may also be citizens of another state or do they prevent their citizens from acquiring multiple citizenships. There are various understandings of dual citizenship and the common belief is that more states tolerate dual citizenship than ever. This master thesis concentrates on the dual citizenship politics in Lithuania. While it seems that at least in Europe the governments tend to allow or tolerate dual citizenship, the dual citizenship regulation in Lithuania is strict and dual citizenship is not tolerated despite the large extent of emigration and emigrants wishes to have the right to dual citizenship. The public debate on the dual citizenship in Lithuania is intense for about a decade now and politicians have been urged to solve this issue many times. However, all the intended changes were stopped by the Constitutional Court of the Republic of Lithuania, leaving no way to solve this unless the Constitution of Lithuania is changed. The politics of dual citizenship in Lithuania in the thesis are analyzed using theoretical framework of the nation-building and the geopolitical thinking in the post-soviet states. First of all, the reasons for the strict regulation of the dual citizenship in The Constitution of Lithuania written in 1992 are analyzed. Second of all, the resistance to the dual citizenship is analyzed in the context of current emigration from Lithuania. The main data was gathered by interviewing experts of the citizenship politics in Lithuania. It is revealed that the political resistance to dual citizenship in Lithuania is the result of the geopolitical insecurity, national minorities residing in Lithuania as well as of Lithuania’s historiography.