Our study aimed at understanding the utilization of research knowledge generated in sustainable development research. Drawing on a sample of 54 recent research projects, we investigated how and by whom the knowledge was used, what changes were achieved, and how non-academic actors were involved. As a conceptual framework we combined a concept of “stages of knowledge utilization” with a spiral model that co-creates three forms of knowledge – systems knowledge, target knowledge, and transformation knowledge, and which spans from joint problem definition to concrete sustainability transformations. We analysed questionnaires from 94 academic and non-academic actors using cross-tabulation, chi-squared tests, and qualitative content analysis. The early involvement of non-academic actors from key groups such as local enterprises was positively related to the utilization of research knowledge, as was their involvement in diverse roles. However, only little of the research knowledge generated has so far resulted in changes in policy and practice, partly because sustainability transformations are larger societal processes. Utilization of research knowledge for sustainability transformations cannot be achieved without employing a transdisciplinary approach that brings together academic and non-academic actors in a setting that enables discussions on an even footing and the empowering of actors who are often not heard. In such settings, researchers are also part of the change rather than mere observers, an additional factor that came up in our participatory results validation activities and that requires further research. For more influence on policies and practice, research for development requires active participation of non-academic actors from the outset, when the project contents are defined.