Popular and partisan reactions to multiculturalism have proven pervasive in societies around the world. As governments work to direct policy toward immigrants, law and order, and social welfare provision, among other areas, populist radical right-wing parties have contributed to the discourse, agendas, and policy responses. Still, scholars debate the precise role of radical right-wing parties and the degree of causal credit due to them. This chapter contends that despite the causal complexity, evidence of RRP impact can be found in contextualized understanding of dynamic interactions within national party systems affected by sociopolitical conditions, actors, and institutions. It examines four indicators of RRP impact with evidence from Western Europe, Eastern Europe, and several other countries around the world. Radical right-wing party impact can be either direct or indirect, as RRPs mediate issue debates, particularly on immigration, multiculturalism, and national identity.