A vast literature suggests that economic inequality hasimportant consequences for politics and public policy.Higher inequality is thought to increase demand forincome redistribution in democracies and to discouragedemocratization and promote class conflict and revolutionin dictatorships. Most such arguments crucially assumethat ordinary people know how high inequality is, how ithas been changing, and where they fit in the income dis-tribution. Using a variety of large, cross-national surveys,we show that, in recent years, ordinary people have hadlittle idea about such things. What they think they knowis often wrong. Widespread ignorance and misperceptionsemerge robustly, regardless of data source, operationaliza-tion, and measurement method. Moreo ver, perceivedinequality— not the actual level—correlates strongly withdemand for redistribution and reported conflict betweenrich and poor. We suggest that most theories about politi-cal effects of inequality need to be reframed as theoriesabout effects of perceived inequality.