It is widely believed that ethnic politics and conflict are less pronounced in countries with cross-cutting rather than reinforcing social cleavages. We argue that one possible explanation is that cross-cutting cleavages facilitate cross-cutting social interaction among individuals from different ethnic and/or class groups. This article examines whether such cross-cutting interaction, relative to homogeneous interaction, can reduce support for ethnic politics and increase support for a cross-ethnic, programmatic alternative. We conduct an experiment in Lebanon in which 720 lower- and upper-class Christians, Sunnis, and Shia were randomly assigned to participate in discussions that varied in their sectarian and class compositions. Our evidence suggests that cross-sectarian discussion resulted in less support for sectarian politics but only when individuals also belonged to the same economic class, driven by greater learning about shared preferences and reduced coethnic social pressure. We also demonstrate the limitations of other forms of cross-cutting discussion, showing that interaction among coethnics or non-coethnics from different classes did not weaken support for ethnic politics. These findings reveal when and how interaction that leverages a second dimension of interest or identity can help shift political preferences, shedding new light on the foundations of support for cross-ethnic politics in ethnically divided societies.