Public doubts about the procedural fairness of elections, whether accurate or not, strike at the heart of citizens’ trust in their political system, exacerbating cynicism, and threatening to weaken political participation. It is therefore worrying that election losers – and sometimes winners – spread false claims of rigged elections in democracies as different as the Philippines, Germany, or the US, while autocrats from Azerbaijan to Cambodia whitewash deeply fraudulent contests. This paper investigates the drivers of public perceptions and misperceptions of electoral integrity by linking public opinion data from 82 national elections with expert survey data on disinformation and de facto electoral integrity. Building on theories of rational belief updating it argues that disinformation campaigns are suited to reduce the accuracy of popular perceptions of election quality. Suggested policy remedies such as third-party corrections via news media or election monitors have only limited scope for inoculating populations against disinformation. The results are somewhat at odds with recent advances in disinformation research that emphasize limited exposure and minimal effects. This contributes a cross-nationally comparative perspective to studies of (dis)information processing and belief updating, as well as attitude formation and trust surrounding highly salient political institutions such as elections, and to research into third-party constraints on electoral manipulation.