Capacity building has been identified as being of importance for the Intergovernmental Science-PolicyPlatform on Biodiversity and Ecosystem Services (IPBES). As the IPBES is becoming an influentialexpert organization, it is essential to examine what capacity building means in its context, what capacitiesit has built, and what implications these capacities have. This study explores these issues byfocusing on the IPBES's general strategy for capacity building, the IPBES's fellowship programme and towhat extent there are additional capacity building needs that can be addressed. The study shows that theIPBES has focused its capacity building efforts on the science side of the science-policy interface while,thus far, it has neglected to build capacities on the policy side of the interface. The study provides insightinto how capacity building for the science-policy interface sets preconditions for science-policy relationsat different levels and scales within biodiversity and ecosystem services and beyond.