The current enthusiasm for circular economy (CE) offers a unique opportunity to advance the impact of research on sustainability transitions. Diverse interpretations of CE by scholars, however, produce partly opposing assessments of its potential bene ts, which can hinder progress. Here, we synthesize policyrelevant lessons and research directions for a sustainable CE and identify three narratives -optimist, reformist and skeptical -that underpin the ambiguity in CE assessments. Based on 54 key CE scholars' insights, we identify three research needs: the articulation and discussion of ontologically distinct CE narratives; bridging of technical, managerial, socio-economic, environmental and political CE perspectives; and critical assessment of opportunities and limits of CE science-policy interactions. Our ndings offer practical guidance for scholars to engage re exively with the rapid expansion of CE knowledge, identify and pursue high-impact research directions, and communicate more effectively with practitioners and policymakers.