This study critically examines greenwashing as a corporate legitimacy strategy within the framework of Environmental, Social, and Governance (ESG), employing a literature review approach. The research is motivated by growing concerns over the use of ESG narratives that project sustainability without reflecting genuine commitments to social and environmental responsibility. Using legitimacy theory as the main analytical lens, the study finds that corporations systematically deploy ESG as a symbolic tool to maintain or gain social legitimacy, often without substantive changes to exploitative business practices. The findings suggest that legitimacy is not merely reactive to external pressures but can be strategically constructed through engineered sustainability narratives. Theoretically, the study expands the application of legitimacy theory in corporate sustainability discourse and calls for a shift from normative-technocratic perspectives to more critical-political approaches in ESG studies. Its policy and social implications include the urgent need for ESG reporting reforms, enhanced accountability and transparency, and stronger civil society involvement in monitoring corporate sustainability claims.