The relationship between the European Union and party politics has remained largely unexplored and under-theorized. Even less attention was given to the linkages between the EU and ethno-regionalist parties. After considering ethno-regionalist parties as the most pro-European party family, recent research showed increasing variation in ethno-regionalist party response to the EU and that the European context for those parties can be an additional dimension in party competition. The present paper contributes to these debates by exploring to what extent the European dimension affects ethno-regionalist party strategies and how this dimension is used in sub-national party competition. After revising most important research, the paper conceptualizes a new theoretical mechanism to explain ethno-regionalist party Europeanization by constructing a bridge between the theories of ethnic party competition and the research on the Europeanization of political parties. The article concludes with an outlook on the relevant case studies and the testing of mechanisms.
