The creation of executive agencies outside core departments has been a major element of administrative reforms throughout Europe during the past two decades, driven by a managerial logic, which also has been at the core of most academic works on "agencification." In this article, the authors take a different perspective by focusing on executive agencies' influence in the policy process. The authors analyze the policy influence of a large executive agency with service delivery tasks in the context of a parliamentary system of government (Flanders, Belgium). A comparison of the agency's influence in two major policy processes shows that a complex interplay of policy content, patterns of interaction, and mutual trust with the political leadership and organizational characteristics helps in explaining the observed patterns of influence. The findings also raise normative concerns regarding potential problems of disconnecting operations from policy formulation via agencification. © 2012 SAGE Publications.