Spain is often referred to as a nation of nations. Ethnocultural differences between the Castilian majority and the Basques, Catalans and Galicians have always been an important issue in Spain. The dual process of state-building and nation-building is of fundamental importance to the territorial structure and the national identities. Spain’s way of dealing with the question of nationalities may also be interesting for other European states. The analysis contains the historical development and the current situation of the different nationalities. Based on a concept defined together with the Carinthian Institute for Ethnic Minorities, the case study provides a political analysis of the situation of the nationalities in Spain. Thus, a multi-level analysis of the existing literature, of journals, newspaper articles and of other material is drawn up.