The concept boundary organization has been introduced to identify and explain a specific way of organizing the interface between science and policy. Although the original meaning of the concept has been criticized, the term has come to be frequently used in studies of knowledge transfer and science-policy relations. This usage constitutes the reason for this paper, which investigates how the concept of boundary organization has come to be used and defined and explores its contribution to the discussion of the organization of the science-policy interplay. The analysis finds that despite its spread and usage, the concept boundary organization does not refer to any specific form of organization and does not per se give any guidance about how to organize science-policy interplay. Instead, boundary organization is mainly used as an empirical label when studying the governance of expertise and the management of science-policy interfaces. This finding is also true for studies of the Intergovernmental Panel on Climate Change, which describe that organization as a boundary organization without saying anything about what that label means in terms of institutional design and practical implications. However, to label an organization as a boundary organization nevertheless works performatively; it shapes an organization’s identity, may provide legitimacy, and can also stabilize the interactions between it and other organizations. Therefore, boundary organization is an important concept, but primarily as a way to facilitate interaction. Thus, the focus of research should be on analyzing how the concept is used and what its implications are for the organization studied.