This chapter deals with the internal decision-making process of political executives in parliamentary systems, that is, how executives take their own collective decisions. The focus is on the cabinet system as a whole, including both cabinet members and other involved party-political and bureaucratic actors. In particular, the chapter reviews literature’s debates about the nature of cabinet government, the role of prime ministers, and variations of decision-making. A special attention is payed to factors explaining intra-cabinet power distribution and the choice of different decision-making arenas. After introducing the topic, an overview of conceptual issues and main research questions is provided. Subsequently, the work discusses the way in which scholars have addressed these issues and the findings they have reached. The final part stresses existing deficits and seeks to set the agenda for future research.