Political parties are crucial agents in the process of democratic representation and the main pool for the recruitment of political elites in European democracies. They are also key agents for the political integration of citizens of immigrant origin, a growing category of citizens constituting around one-fifth of the population in many member states of the European Union. Voter studies have established that citizens of immigrant origin are less likely to vote than citizens without an immigrant background. There is less research on such citizens to join political parties, especially in comparative politics accounting for macro-level variation. Based on a theoretical model combining standard individual predictors of political involvement (especially SES variables and nationality) on the one hand and macro-level information on the structure of political opportunities (e.g., properties of the party system, electoral system, voting rights for non-citizens) on the other, we will use pooled data from the 9th wave of the ESS (2018) to, firstly, fit a general multi-level model of involvement in political parties. In a second step, we will examine key conditions for political integration by comparing first-generation and second-generation immigrants to citizens without recent immigration background. The results will have implications for migration studies as well as for the discussion over the (declining) ability of political parties to recruit members.