This paper examines the processes and factors that influence the production of a salient, credible and legitimate Cambodia’s National REDD+ Strategy (NRS). Findings are presented in two parts. First, it empirically reveals that while many working drafts were produced and consulted with more than 1,000 stakeholders from local to international level, finalization of the NRS is still pending as of December 2016. The second part then theoretically explains this empirical finding through concepts in sustainability science, in particular effective boundary work, defined as negotiation processes that happen at the interface between relevant scientists and policy-makers with different views of what constitute salient, credible and legitimate knowledge. This paper makes the central argument that while boundary work does contribute to stakeholders’ perceptions of the Cambodian NRS as salient, credible and legitimate, the effectiveness of this boundary work depends on the combined impacts of contexts and boundary agents. Although contexts for the NRS production are characterized by multiple sources and users of knowledge, this paper found that the former is less significant than the latter. It also found that in highly politicized contexts, boundary work is performed through boundary agents, instead of the formally established institutional arrangements. Boundary agents are defined by their abilities to facilitate communication, translation and mediation of the different political and personal interests that stakeholders bring into the policy process. This paper concludes that the process to develop a salient, credible and legitimate NRS is both a technical and political exercise.