This article examines mass public discourse on religion and pluralism in diverse societies. It argues that religion enters the public sphere by defining countervailing narratives about sectarianism, which is exclusive and divisive, and ecumenicism, which is inclusive and unifying. Most empirical studies focus on elites as the producers of discourse and ignore the regular people who comprise the “real” public. In contrast to prior work, this article systematically examines mass public discourse, with Lebanon, a religiously diverse developing world society, as its research venue. It uses a novel combination of original survey data and publicly displayed religious and political iconography to study the exchange of ideas about religion and pluralism among the mass public. It shows that sectarian discourse articulates ethnocentric and antiplural statements, whereas ecumenicism, by contrast, mitigates ethnocentrism and valorizes pluralism.