"Multiculturalism has utterly failed", German Chancellor Angela Merkel declared inOctober 2010, "immigrants need to do more to integrate in German society". A few months later, in February 2011, British Prime Minister David Cameron also condemned his country's long-standing policy of multiculturalism as a failure, claiming that many young British Muslims were drawn to violent ideology because they found no strong collective identity in Britain. These two quotes from leading European politicians exemplify how migration and multiculturalism have become key issues in contemporary societies. Virtually all countries in the world need to deal with the steady flow of people crossing international borders that have made societies in our globalized world more and more diverse. Despite its contested nature as a normative model for organizing diversity in receiving societies, multiculturalism has become an inescapable reality to which countries need to adapt.This chapter is concerned with two major questions concerning migration and multiculturalism. First, it looks at the social and psychological processes at work in the migrant experience. Second, it deals with how members of receiving societies react to the increased and diversified immigrant presence in their societies. 1 Our review draws mainly upon research and theory in political and social psychology. Reflecting the diversity of classic and recent empirical work on migration and multiculturalism, we present research covering a Migration and multiculturalism 2 wide range of methodological approaches, including survey, experimental and qualitative studies. The chapter emphasizes how historical and political contexts affect the nature of intergroup relations between migrant groups and receiving societies. It furthermore highlights the role of widely shared social representations in processes of migration and multiculturalism, expressed in ideological belief systems, political discourse and everyday cultural repertoires. We argue that a political psychology perspective to migration and multiculturalism will gain from taking a interdisciplinary approach in which different levels of analysis-including individual, group and societal factors-are combined and articulated (Castles & Miller, 2009;Chryssochoou, 2004;Deaux, 2006;Verkuyten, 2005a).The chapter is organized in four parts. The first part outlines some historical benchmarks of modern migration and briefly presents two key notions of a psychological approach to migration-assimilation and multiculturalism-in their historical context. In a second part, we summarize empirical research that focuses on the psychological dynamics involved in the migrant experience, in particular the interactionist and complex nature of migrant identities, acculturation and adaptation in receiving societies, and intergroup approaches to acculturation and multiculturalism. The third part analyses the role of threat regarding immigrants and immigration in the reactions, attitudes and beliefs of majority populations in receiving societies. The...