LGBT rights have come to be seen as allied with the idea of “Europe” and a European identity, particularly in the process of European Union enlargement to the East. Scholars have examined the ways in which external norms interact with more local, often “traditional” norms and identities. In this process, nationalism and conceptions of national identity and gender/sexuality norms can be seen as important factors that influence the domestic adoption of LGBT rights, particularly in the post-war Balkans. Croatia and Serbia (from approximately 2000 to 2014) present two interesting and different cases to analyze how discourses and dynamics of national and state identity construction, nationalism, and LGBT rights relate to discourses of “Europeanness” and European identity and how these affect the political dynamics of LGBT rights. This article finds that in Croatia, national identity was constructed in terms of convergence with European norms and identity, homonationalism was used to distinguish themselves from a “Balkan” identity, and there was a lower threat perception of the LGBT community framed primarily as a “threat to the family.” In Serbia, state and national identity was constructed in opposition to Europe and homosexuality had stronger threat perception, framed primarily as “threat to the nation.” In short, nationalism and national identity were less disadvantageous as a domestic constraint to LGBT rights in Croatia than in Serbia. The dynamics between nationalism and LGBT rights played out, for example, in the politics of the marriage referendum, Pride Parades, and public discourse more generally. This research contributes to the scholarship on LGBT rights and nationalism by empirically analyzing the different ways that nationalism, gender/sexuality, and European identity interrelate and influence LGBT rights change in a changing post-war identity landscape and how domestic constraints affect human rights norm diffusion.