Both in literature and in practice, it is claimed that joint knowledge production (JKP) by researchers, policy makers, and other societal actors is necessary to make science relevant for addressing climate adaptation. Although recent assessments of JKP projects have provided some arguments in favor of their societal merit, much less is known about their scientific merit. We explored the latter by developing a conceptual framework addressing characteristics of doing JKP as well as hypotheses on potential merits and pitfalls in terms of its process, output, and impact for science. Semistructured interviews with six environmental science research leaders as well as discussions with five researchers involved in past JKP projects were used to start operationalizing the framework into criteria and compiling a survey. This survey was filled out by 144 researchers involved in Knowledge for Climate, a large Dutch multiactor research program. The findings suggest that, at least in the context of recently carried out Dutch climate adaptation projects, JKP contributes to a broader empirical knowledge base; more reflexivity on the part of researchers; and more publications for policy makers. We conclude this paper by formulating next research steps, including evaluating what would be a proper balance between more versus less participatory forms of scientific knowledge production.