Most global inequality is between countries, but inequality perceptions have mostly been investigated within the country. Six studies (total N = 2656, 5 preregistered, 1 incentivized for accuracy, 1 with a sample representative of the USA) show that Westerners (U.S. American, British, and French participants) believe that developing and middle-income countries’ GDP per capita is much closer to developed countries’ than it actually is, and that people in developing and middle-income countries have higher rates of car ownership, larger houses, and eat out more frequently than they actually do, meaning that Westerners underestimate global inequality. This misperception is underpinned by a convergence illusion: the belief that over time, poorer countries have closed the economic gap with richer countries to a larger extent than they have. Further, overestimating GDP per capita is negatively correlated with support for aid to the target country and positively correlated with a country’s perceived military threat. We discuss implications for inequality perceptions and for global economic justice.