This article addresses an understudied aspect of public secularity in the Canadian province of Québec, namely how its self-perception as a postcolonial nation vis-à-vis English Canada has shaped its secular state building since the 1960s. In so doing, it shows that postcolonial legacies and imaginaries, a key theme for studying secularity in non- Western cases, may also prove decisive for the North Atlantic world. The historical account proceeds in two parts. In the first period (1960-1980), the Quiet Revolution's rapid disestablishment of Catholicism was intimately linked to its anticolonial spirit, where the Church was identified as an obstacle to economic development and political self-determination. In the second period (post-1980), the consolidation of Canadian multiculturalism and the challenge of immigrant religions led to a contradictory form of "cultural defense" (Martin 1978): an increased emphasis on the Catholic heritage as well as on laïcité, both underscoring Québec's unique identity in distinction from English Canada. Demonstrating the effect of postcolonialism in a North Atlantic example, and nuancing the concept of cultural defense by identifying its religious and secular forms, the article emphasizes the prospect of a common ground in the analysis of Western and non-Western secularities. [ABSTRACT FROM AUTHOR]