The vast majority of democracies in existence today operate under a parliamentary form of government. Despite this, and in stark contrast with scholarship on presidentialism, the research literature on the design, evolution and consequences of parliamentary government is surprisingly sparse and rudimentary. This paper provides the first systematic overview of the institutions of parliamentarism, exploring differences in government formation and resignation rules, restrictive legislative procedures, executive decree powers and assembly dissolution mechanisms. We define and trace the origins of and change to the core institutions of parliamentarism, and show that institutions of parliamentarism have been increasingly codified or designed in a way to strengthen the executive at all moments of its existence – formation, policy-making and termination. We will also argue that these trends do not imply that there is a parallel process of executive appropriation of parliamentary powers.