Abstract. The article addresses social and political conflicts with a clearly defined ethnic component in the modern Spanish society. Assessing the experience of regulating interethnic and interterritorial relations between Spanish nationalities and regions, the mass immigration of diverse cultural backgrounds in the asymmetric State of Autonomies, the author examines competitive identity politics and public discourses on nation, nationalism and nation-building. Voiced by the central and subnational authorities, it frequently assumes a conflict character. This is especially customary for Catalonia, but also applies to the Basque Country and several other autonomous regions. Education and language policies are a sphere of clashing perceptions and a key priority for politics of identity involving central and regional authorities, political parties and civil society groups. The increasing phenomenon of the ethnicity politicization in the State of Autonomies complicates the formation of the civic (national) identity and enhances the potential of ethnopolitical conflicts in the country, where particularistic sentiments are sufficiently strong in the historical perspective, while the mass foreign migration introduces new interethnic and intercultural contradictions and challenges. The Spanish experience of interethnic and interterritorial relations regulation and of positive civic identity construction in the context of the federalizing State of Autonomies may be useful for the Russian Federation having some similar problems on the agenda and a continuously developing model of federal structure.