Various strands of literature in comparative politics regard governments as the only noteworthy initiators and mainsprings of legislative policy making in parliamentary democracies. Opposition activity in policy making is more often associated with the intention to prevent, rather than to shape, policy. Does this perception reflect real‐life politics? To answer this question, this article discusses different arguments that link institutional and policy‐related characteristics to the incentives and constraints of different government and parliamentary actors to initiate or co‐sponsor legislative bills. More specifically, it relates policy‐, office‐ and vote‐related incentives, as well as institutional and resource constraints of legislative actors, to the likelihood that these actors will take the lead in legislative agenda‐setting. These arguments are confronted with original data on the universe of all legislative bills in four parliamentary systems over one and a half decades. The article concludes that opposition and, in particular, bipartisan agenda‐setting is indeed rare. Yet, in contrast to widely held maxims, it is neither absent nor spurious, but related to the allocation of power and the intensity of ideological conflict both within and between the (coalition) government and parliament.