An extensive literature links the rise of populist radical right (PRR) parties to immigration. We argue that another demographic trend is also significant: emigration. The departure of citizens due to internal and international emigration is a major phenomenon affecting elections via two complementary mechanisms. Emigration alters the composition of electorates, but also changes the preferences of the left behind. Empirically, we establish a positive correlation between PRR vote shares and net-migration loss at the subnational level across Europe. A more fine-grained panel analysis of precincts in Sweden demonstrates that the departure of citizens raises PRR vote shares in places of emigration and that the Social Democrats are the principal losers from emigration. Elite interviews and newspaper analyses explore how emigration produces material and psychological grievances on which populists capitalize and that established parties do not effectively address. Emigration and the frustrations it generates emerge as important sources of populist success.