It is increasingly recognised that co-construction of knowledge which brings together researcher-derived understanding, with local, practitioner or non-researcher understanding is necessary to address current global challenges. Emerging empirical evidence suggests challenges remain in bridging across scales and ensuring inclusion of the marginalised. It is unclear whether espoused approaches are in practice enhancing the wellbeing of those currently on the front lines of ecological, social and political crises, or, whether they are inadvertently increasing inequality. In this article, we explore co-construction from our experience as embedded researcher–practitioners through two case studies: the ecological restoration of fisheries by the Skolt Sámi in Finland, and the conservation of agro-ecological and forest management practices by peasant communities in Paraguay. We challenge the idea that co-construction of knowledge is sufficient to engage with regressive institutional and political dynamics that continue to marginalise, arguing for a focus on self-determination to be the foundation for co-construction.