The aim of the project is to analyse the determinants and implications of party competition in the regional sphere in European multi-level systems. In doing so, the project addresses three main research questions. First, do parties on the sub-national level respond to the structural characteristics and ideological orientations of the regional electorate when formulating their election manifestos? In a second step, the project will deal with the question of what impact the different types of regional authority, the patterns of national party competition and the programmatic profiles of sub-national parties have on the outcome of the coalition formation and portfolio allocation processes at the regional level. Third, the project seeks to analyse the impact of regional governments and their partisan composition on policy outputs. To answer these questions, the project builds on theories relating to party competition and government formation in multi-level systems and the principal-agent approach. To test our hypotheses, we use a dataset that covers information on issue saliencies and policy positions of political parties at the regional and national level in nine European states.