This study, entitled “Closing the Knowledge Gap between Research, Policy and Practice: Circular Knowledge Exchange on African Indigenous Vegetables for Improved Food and Nutrition Security in Kenya and Tanzania”, focuses on disseminating research results from the HORTINLEA project to diverse stakeholders including policymakers, farmers, and other actors along the African Indigenous Vegetable (AIV) value chain. It defines three research objectives: analyse local innovation processes and adoption criteria; develop target-group-specific dissemination instruments; and conceptualise an AIV knowledge and innovation network. Conducted in Kenya, Tanzania, and Germany, the study adopts an Integrated Agricultural Research for Development (IAR4D) framework and the Innovation Systems Perspective. It investigates interactions between small-scale farmers, researchers, and policymakers, aiming to improve cooperation within the innovation and dissemination process. Sustainability—ecological, economic, and social—is treated as a cross-cutting issue. A mix of qualitative and quantitative methods, including 114 interviews, 60 questionnaires, and 15 focus groups, was employed. Findings reveal that farmer involvement from the outset and trust in intermediaries are crucial. Adoption is influenced by process and innovation criteria, with training being most important. The study proposes manuals and policy briefs as dissemination tools, and introduces a strategy for establishing a Knowledge and Innovation Network (KIN) to sustain circular knowledge exchange. Recommendations call for shifting from top-down to participatory approaches, integrating farmers throughout the innovation process. The study concludes that closing the knowledge gap between research, policy, and practice through inclusive networks and tailored dissemination instruments is essential for sustainable development impact.