Contemporary radical right‐wing populism is generally associated with nativism, usually defined as an intense hostility to anything deemed alien and threatening to national cohesion. This article explores the origins and evolution of nativism in three major nineteenth‐century populist movements – antebellum Know Nothingism and post‐civil‐war agrarian populism in the United States and late nineteenth‐century Boulangism in France. All of them advanced nativist propositions to bolster their populist agenda, yet not of the same nature and to the same extent. These differences can largely be explained by the targets of populist mobilization and the constituency at which it was aimed. The cases suggest that nativism plays an important role in populist mobilization, not least because it allows populist movements to transcend differences between social groups and gives them an opportunity to promote themselves as the champions of collective identity – a concern central to the contemporary radical populist right.