The social landscape in Southeast Europe has changed dramatically over the past twenty years: increased globalization, new migration and mobility patterns, the refugee crises, economic uncertainty, and the emergence of other salient identities, have all influenced the region dramatically. However, while the continent-wide increase in Euroskepticism, right-wing populism, and disillusionment with globalization points to the need for examining new solidarities and new permutations of difference, research on the effects of these social changes is scarce. In the following articles, we examine the new cleavages and new solidarities created by these changes: effects of global phenomena such as international youth exchange programs, music/film festivals, language, diaspora and dual citizenship, and migration, and the ways in which they are assuaging or amplifying ethnic tolerance in the region, exploring both the determinants of these societal changes, as well as the effects of the changes: emerging political issues and cleavages, new intersections of identities, and new forms of ethnic (in)tolerance.