Although the role of international organizations in the diffusion of education policy is widely acknowledged, their role in the articulation of policy ideas remains comparatively underresearched. This article addresses this gap through a case study on the role of the OECD in the construction of the School Autonomy with Accountability policy model--a governance approach that grants schools greater decision-making capacity in exchange for more intensive monitoring mechanisms. Informed by a combination of interviews and documentary analysis, our article shows that the construction of the model within the OECD has followed different stages, with the model enjoying varying levels of visibility, contestation, and universalist ambition in each of them. The article shows that model construction is an erratic process affected by the interplay of different forms of expertise and hierarchies, and it cautions against totalizing narratives that portray international organizations as coherent all-powerful entities.