In the domain of climate change adaptation we see various efforts at joint knowledge production (JNP) through intensive cooperation between scientists, policymakers and other actors. Regional climate change adaptation projects in The Netherlands form prominent examples of this. In literature and in practice, claims have been made that joint knowledge production provides a useful way to reconcile supply and demand for knowledge. However, there is a lack of systematic empirical studies on how to successfully ‘do’ this. Existing research is restricted to conceptual analyses and fragmented empirical studies. This paper, on the contrary, aims to generate design principles. It does so by confronting a previously-developed assessment framework with empirical reality in six Dutch adaptation projects. Project documents were studied and 30 semi-structured interviews with researchers, policymakers and project financiers in the projects were held. Based on the comparison, the paper derives and elaborates upon two design principles for JNP. First, we have seen that the most successful projects managed to create some distance (a protected niche) for knowledge development, while at the same time establishing connections with ongoing policy processes. Successful JNP seems to be more likely in cases in which actors make a conscious decision for the institutional location of the project on the research-policy nexus, whereby the coordinating entity has some characteristics of a boundary organization. Second, specific resources, including facilities, boundary objects and specific competences increase the chance for success. In conclusion, the paper reflects on the external validity of the analysis and identifies next steps towards developing an empirical knowledge base for JNP. ; September 2012