Policy scholars have long studied the phenomenon of policy advice, with the aim of understanding variations in the professional practice of policy analysts and other civil servants. The quest for theorizing the selection and use of advice and information in the policy process has triggered several attempts of typologizing the many facets of policy advice: the location and autonomy of the advisors, their roles, the content of advice, as well as the styles of policy advisors. The styles of policy advice bring attention to the standard operating procedures which influence the content and use of policy advice. This chapter develops a synthetic typology of styles of policy advice with a descriptive and explanatory purpose. First, the suggested typology can help in mapping the procedures of advising within policy advisory systems (PASs) in various jurisdictions. Second, the typology invites a series of explanations of why different governments or subsystems privilege one style of advice-making over the other. The typology takes stock of the latest developments in the fields of public policy and public administration, in particular the conceptualization of PASs as extending beyond the government sphere and the collaborative turn in governance research.