This study explores how news messages carrying parts of the populist ideology contribute to a polarization of public opinion about populism. It combines a content analysis of news coverage on two policy areas (N = 7,119 stories) with a two-wave panel survey (N = 2,338) in four European metropolitan regions (Berlin, Paris, London, and Zurich). In three regions, unopposed media messages with a populist stance have a conditional effect on populist attitudes that depends on prior convictions. A higher dose of exposure to populist news coverage enhances both prior agreement and disagreement with populism. Although the observed interaction patterns vary between regions, the general picture suggests that populist messages in the news foster polarization between public support and disapproval of populism.