AbstractContemporary U.S. politics is characterized by polarization and interpartisan antipathy. This is accompanied by a media landscape saturated with coverage of political scandals. Applying a social identity perspective, we examined whether exposure to scandals that threaten partisan's moral group image (i.e., in‐party scandals), may motivate defensive hostility against opposing partisans. Across three experiments we exposed U.S. partisans to scandals attributed to either in‐party or out‐party politicians. We then assessed partisan hostility using a variety of operationalizations, including anger at a real outgroup politician (Study 1), judgments about the alleged misdeeds of a fabricated outgroup politician (Study 2), and negative perceptions of opposing party members (Study 3). Strength of partisan identity was assessed as a predicted moderator (Study 3). As expected in‐ (vs. out‐) party scandals, were perceived as group‐image threats and elicited greater hostility towards opposing partisans, independent of partisans' ideological extremity or prior affective polarization.