This paper analyses how 'criticality' is negotiated in the global policy frameworks on Education for Sustainable Development (ESD) and re-conceptualised in Vietnamese ESD policymaking. Taking the context of Viet Nam, this paper reflects on what constitutes criticality in education in the light of cultural and historical contexts of the education systems. The comparative perspective helps explore whether (1) universal or decontextualised 'criticality' exists or (2) whether 'criticality' is culturally negotiated based on the premise that educational imaginaries of societal formation and transformation are historically and contextually embedded and contingent. In addition, this paper connects the ongoing debate on the critical potential of ESD within the field of environmental education (EE) research to comparative education research by highlighting both what a comparative perspective might offer to EE research and what recent developments in EE research might contribute to comparative education research.