The Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) is an expert institution set to transform the governance of biodiversity and ecosystem services. IPBES expands on previous initiatives and positions itself as a knowledge-policy interface open to different ways of knowing biodiversity. In this contribution, we analyse how the principles of regional, gender and disciplinary balance that were adopted by IPBES have been applied to the Multidisciplinary Expert Panel (MEP): the body of experts responsible for the scientific and technical function of IPBES and embedded in its knowledge-making practices. In doing so, we compare the selection of the interim MEP in 2013 with the new MEP in 2015 and find a small improvement in gender and disciplinary balance that varies across the United Nations regional groupings. According to the ambition of IPBES there is significant room for improvement, but ‘opening-up’ expertise in an intergovernmental setting proves challenging.