Transdisciplinary research is considered to offer contributions of science to sustainability transformations, partly because transdisciplinary approaches aim to increase the relevance, credibility, and legitimacy of scientific research by ensuring the active participation of non-academic actors in research. However, the possible impact of transdisciplinary research on decolonial sustainability science – understood as actively undoing Euro-North American centricity, dispossession, racism, and ongoing power imbalances in inequitable social-ecological systems – and simultaneous response to scientific rigor remain under debate. Thus, this article assesses the contributions of transdisciplinary research projects to decolonial sustainability science based on empirical information. To do so, we analyze a sample of 43 development research projects of the Swiss Programme for Research on Global Issues for Development (r4d programme) in Africa, Asia, and Latin America. We found that despite significant differences in approaches, Global-North-dominated sustainability science still has far to go to achieve the decolonial potential of transdisciplinarity, enabling different actors’ participation.