This article attempts to explain how international governmental organizations (IGOs) become autonomous. It argues for a conceptual shift to an organizational studies perspective that puts the concept of the organization at the center of attention. Although some approaches in IR already apply particular organizational theories, an open‐system perspective offers a promising representation of IGOs, their internal dynamics, and external relations. Within an open‐system perspective, modern system theory is useful for examining how autonomization processes can be explained by taking into account the momentum of self‐referential closure on the basis of decisions.