The State of the River Nile Basin Report (SOB) 2021 for the Nile River provides a knowledge basis for transboundary water resource management. Building on the 2012 SOB and on behalf of the Nile Basin Initiative (NBI), the authors examine the impacts of human activities on water and other natural resources and assess progress toward goals set by the riparian countries for sustainable resource use. Based on a comprehensive set of indicators, the SOB enables ongoing monitoring of the effectiveness of implemented water resource management measures besides the environmental state of the river basin. This way, the report is intended to promote cooperation between the various water-relevant stakeholders across national borders, which is an important prerequisite for the sustainable and equitable use of the Nile Basin's resources.