This article investigates the impact of populist messages on issue agreement and readiness for action in 15 countries (N = 7,286). Specifically, populist communicators rely on persuasive strategies by which social group cues become more salient and affect people's judgment of and political engagement with political issues. This strategy is called ‘populist identity framing’ because the ordinary people as the in‐group is portrayed as being threatened by various out‐groups. By blaming political elites for societal or economic problems harming ordinary people, populist communicators engage in anti‐elitist identity framing. Another strategy is to blame immigrants for social problems – that is, exclusionist identity framing. Finally, right‐wing political actors combine both cues and depict an even more threatening situation of the ordinary people as the in‐group. Based on social identity theory, an experimental study in 15 European countries shows that most notably the anti‐elitist identity frame has the potential to persuade voters. Additionally, relative deprivation makes recipients more susceptible to the mobilising impact of the populist identity frames.