In contrast to the conservative values of rural populations, cities are often seen as bulwarks of more tolerant, liberal and progressive values. This urban–rural divide in values has become one of the major fault lines in Western democracies, underpinning major political events of the last decade, not least the election of Donald Trump. Yet, beyond a small number of countries, there is little evidence that cities really are more liberal than rural areas. Evolutionary modernisation theory suggests that socio-economic development may lead to the spread of progressive, self-expression values but provides little guidance on the role of cities in this process. Has an urban–rural split in values developed across the world? And does this gap depend on the economic development of a country? We answer these questions using a large cross-sectional dataset covering 66 countries. Despite the inherent challenges in identifying and operationalising a globally-consistent definition of what is ‘urban’, we show that there are marked and significant urban–rural differences in progressive values, defined as tolerant attitudes to immigration, gender rights and family life. These differences exist even when controlling for observable compositional effects, suggesting that cities do play a role in the spread of progressive values. Yet, these results only apply at higher levels of economic development suggesting that, for cities to leave behind rural areas in terms of liberal values, the satisfying of certain material needs is a prerequisite.