As the OECD and UNESCO increasingly work in the same geographical and thematic areas, this paper explores the interplay between the organizations in relation to the making of global learning metrics and the global monitoring of the Sustainable Development Goal 4. Although the organizations seek to cooperate, this paper shows how this is limited by differences within and between the organizations -- differences which relate to their global leadership, their understandings of education, the expertise they draw on, and their approaches to Member States. The paper demonstrates the continuation of an established struggle and interdependency between the organizations as they seek to assert their legitimacy in the context of SDG4.