International civil servants, while long neglected, have recently received renewed attention, focusing especially on the their capacity to influence outcomes in international organizations. Xu and Weller, writing in the context of the WTO, suggested that the capacity of the international civil service to achieve designated objectives is affected by both the formal institutional conditions of the organization and the informal opportunities they develop. The Xu and Weller findings raise the question as to whether their model holds in other international organizations, and in this article we explore these issues in the Organization for Economic Cooperation and Development. We find that, while the significance of the factors they discuss is confirmed, the expertise of the Secretariat in the OECD is an important factor at the base of its influence, confirming a similar account of the World Bank.