Transdisciplinarity From Principles to Practice: Insights From <scp>EU</scp> Horizon Research Projects on Sustainability

ABSTRACT Transdisciplinary research (TD) is widely invoked to tackle complex sustainable‐development challenges by integrating scientific and societal knowledge and fostering collaboration among researchers, decision‐makers, practitioners and affected publics. Yet we still lack a refined understanding of the conditions that enable TD to succeed in EU research settings. We address this gap by analysing in‐depth, semi‐structured interviews with Horizon project coordinators working on sustainability topics. Our results reaffirm established enablers—broad and inclusive participation, robust knowledge integration, and balanced, adaptive governance—and surface additional, actionable levers: structured feedback and iterative learning, methodological flexibility, pathways for post‐project continuity, and effective use of digital collaboration tools. We synthesise these insights into a practice‐proximate framework that prioritises power‐sharing, equitable dialogue and shared decision‐making, thereby strengthening the credibility, salience and legitimacy of TD outputs. The article refines existing TD and joint‐knowledge‐production perspectives and offers concrete guidance for researchers, funders and policymakers seeking to design and steward more successful TD processes in future Horizon programmes.