The aim of this project is to identify the set of mechanisms underlying the process of democratization that took place in Luxembourg, starting in the second half of the nineteenth century and culminating in the adoption of universal suffrage in 1919. Political science literature on the emergence of constitutional states in the former Low Countries has focused primarily on Belgium and the Netherlands, overlooking the specificities of Luxembourg’s political development. To the extent that Luxembourg’s democratization has been considered at all, it has standardly been assumed to have followed a trajectory similar to its neighbors’ paradigmatic cases. Using a mechanism-based approach and systematic comparison, the current project seeks to address this lacuna by investigating both the elite and popular levels as complementary sources of democratization. At the elite level, the planned analysis will seek to identify the causal pathway connecting ideational forces to liberal institutional changes, building off the widespread conjecture in historical accounts that liberal ideas are essential for the development of constitutional rights. At the popular level, we will explore the overall low level of contention within the Luxembourgian political realm. Given the emphasis placed by major scholars on the importance of substantial popular contention in successfully challenging established authoritarian oligarchies and opening the way to political participation, the relative low intensity of conflicts in Luxembourg has been considered by some as a sign of lack of support or even “passivity” of the population towards democratic achievement. If democratization actually did unfold in Luxembourg without substantial contention (and thus popular support), this country may be considered a “deviant case” with respect to its western European neighbors. Addressing these issues will require two analytic methods: a Protest Event Analysis assessing the longitudinal features of the various modes of action adopted at the popular level in episodes of contention in Luxembourg and an analysis of political discourses expressing liberal ideas. The foreseen results will shed new light on Luxembourg’s political and democratic development and enrich the theory of democratization with detailed analysis of a new and somewhat puzzling case.