© 2019, © 2019 The Editor of Ethnopolitics. While territorial integrity is largely described as the norm in post-1945 Western Europe, this article shows that it is not one in twentieth century history. This article examines the post-World War I formation of the Kingdom of Yugoslavia at the Paris Peace Conference and the internationally supervised formation of the post-Yugoslav states in the 1990s. It argues that each time multinational entities dissolved and new states were formed in the name of self-determination, territorial rescaling had direct consequences for the status and rights of domestic populations leading to ethnic and citizenship stratifications further supported by international supervisory regimes.