We present and analyze 10 case studies of participatory river-basin management that were conducted as part of the European HarmoniCOP project. The main theme was social learning, which emphasizes the importance of collaboration, organization, and learning. The case studies show that social learning in river-basin management is not an unrealistic ideal. Resistance to social learning was encountered, but many instances of social learning were found, and several positive results were identified. Moreover, 71 factors fostering or hindering social learning were identified; these could be grouped into eight themes: the role of stakeholder involvement, politics and institutions, opportunities for interaction, motivation and skills of leaders and f...