In this paper we document the impact of immigration on political support for welfare state expansion, using national election data of twelve European countries between 2007 and 2016. We match individual information on party voting with a classification of the political agenda of 126 parties during 28 elections. We first investigate the impact of local immigration on individual voting behavior, keeping the political platform of parties fixed. We then shift focus from voters to political parties, and investigate how immigration affects the political agenda of European parties. To attenuate omitted variable and selection bias concerns, we implement an instrumental variable approach that exploits cross-regional variation of immigrant settlements in 2005, along with the skill and nationality composition of recent immigrant flows. We find that larger inflows of highly educated immigrants are associated with European citizens shifting their votes toward parties that favor expansion of the welfare state. On the other hand, inflows of less educated immigrants induce European parties to endorse platforms less favourable to social welfare.