This study aims to discover the corporate social responsibility (CSR) practices implemented by Vietnamese businesses and to shed light on their specific initiatives to promote environmental sustainability. We selected several renowned companies in Vietnam for sustainable development initiatives to study. By applying the content analysis method to sustainability reports of these companies from 2018 to 2022, we categorized and analyzed how these companies have implemented CSR practices to promote environmental sustainability. Our findings confirm a growing recognition among businesses in Vietnam regarding the significance of incorporating CSR into their overarching strategies. Consequently, these entities have engaged in a series of initiatives designed to minimize their environmental impact and contribute to sustainable development. Notable actions include adopting eco-friendly technologies, reducing greenhouse gas emissions, proactive waste management and recycling, and supporting environmental conservation endeavors. The case studies effectively highlight the positive outcomes of these initiatives, such as improved environmental performance, heightened corporate reputation, and increased stakeholder engagement. These case studies in Vietnam serve as compelling evidence that CSR has an indispensable role to play in promoting environmental sustainability. Firms possess huge potential to address environmental challenges by incorporating CSR practices into their operations. This study provides valuable insights and several implications for policymakers, businesses, and other stakeholders committed to leveraging CSR to enhance environmental sustainability.