The European Union (EU) is considered to be a unique economic and political union that integrates most European countries. This article focuses on the cultural aspect of European integration, which has been increasingly debated over the course of deepening and widening integration and in the context of the legitimation crisis of the EU. Among the main goals of the EU is to promote certain values, which raises the question of whether it has been efficient in (or enabled) reducing cultural value gaps among the participating countries. World polity and institutional isomorphism theories suggest that cultural values may trickle down in a vertical manner from the institutions of the EU to its member states and candidates. Furthermore, hybridisation theory postulates that values diffuse horizontally through intensified interactions enabled by the EU. These two perspectives imply the possibility of cultural convergence among countries associated with the EU. By contrast, the culture clash thesis assumes that differences in cultural identity prevent value convergence across countries; growing awareness of such differences may even increase the pre‐existing cultural value distances. To test these different scenarios, distances in emancipative and secular values are compared across pairs of countries using combined repeated cross‐sectional data from the European Values Study and the World Values Survey gathered between 1992 and 2011. This study finds that the longer a country has been part of the EU, the more closely its values approximate those of the EU founding countries, which in turn are the most homogenous. Initial cultural distance to the founders’ average values appears irrelevant to acquiring membership or candidacy status. However, new member states experienced substantial cultural convergence with old member states after 1992, as did current candidates between 2001 and 2008. Since 1992, nations not participating in the integration process have diverged substantially from EU members, essentially leading to cultural polarisation in Europe. The findings are independent of (changes in) economic disparities and suggest the importance of cultural diffusion as one of the fundamental mechanisms of cultural change. This empirical study contributes to the literature on European integration, political and sociological theories of globalisation, and cross‐cultural theories of societal value change.