Abstract: The integration and use of Indigenous knowledge to inform contemporary environmental policy decisions and management solutions is a growing global phenomenon. However, there is little critical inquiry about how the interactions between scientific and Indigenous knowledge (IK) systems can be effectively negotiated for the joint management of social-ecological systems. Such issues are urgent on Indigenous lands where co-management efforts respond to pressing conservation agendas and where the contribution of scientific knowledge and IK is required to better understand and manage complex social-ecological systems. We draw on the notion of boundary work to examine how interaction at the boundaries of scientific and IK systems can be managed effectively as a contribution to co-management. The case study of feral animal co-management in Australia’s Kakadu National Park illuminates the work required for local co-managers to bridge the divide between scientific and IK systems and to ensure the translation of knowledge for management decisions. Attributes of effective boundary work demonstrated in this case include: meaningful participation in agenda setting and joint knowledge production to enable co-managers to translate available knowledge into joint feral animal programs, Indigenous and non-Indigenous ranger efforts to broker interactions between knowledge systems that are supported by co-governance arrangements to ensure that boundary work remains accountable, and the production of collaboratively built boundary objects (e.g., feral animal impact assessment data) that helps to coordinate local action between co-managers. This case study illustrates the contribution of boundary work to local co-manager efforts to translate across knowledge systems and across the knowledge-action divide, even when consensus is difficult to achieve.