Other effective area-based conservation measures (OECMs) create an opportunity to rethink what constitutes conservation by recognizing areas that may not have a conservation objective but that deliver conservation outcomes. In 2010, OECM was introduced as a term during negotiations for the Convention on Biological Diversity’s Aichi Target 11, which aims to protect 17% of the terrestrial and 10% of the marine environment by 2020. Canada has achieved the marine portion of this target, largely due to its implementation of marine OECMs. This thesis explores Canada’s interpretation of marine OECMs, drawing on 13 semi-structured expert interviews. First, the transformation of the OECM concept across different scales of governance is revealed through Kingdon’s policy-window framework, which demonstrates Canada’s narrow interpretation of marine OECMs as marine refuges. Second, critical perspectives on political ecology and global environmental governance are used to identify the opportunities (to recognize Indigenous-led conservation and expand conservation partners) and constraints (of the Canadian state’s technocratic knowledge regime) introduced by this new designation.