Vietnamese banks play a crucial role in facilitating the transition toward a green and environmentally sustainable economy. This study aims to develop a comprehensive theoretical framework and empirically assess the relationship between green banking practices and environmental performance, with a specific focus on the mediating roles of green finance, the social enterprise support ecosystem, and green product innovation. The research focuses on commercial banks in Ho Chi Minh City, particularly those with strong green banking disclosure rankings during the 2016-2022 period. Primary data was collected via an online survey, resulting in 143 valid responses after screening. The data was analyzed using measurement models, structural equation modeling, and hypothesis testing through the bootstrapping technique. The findings reveal that green banking practices significantly enhance environmental performance through the mediating role of green finance. Moreover, green finance directly improves environmental performance and indirectly influences it via the social enterprise support ecosystem and green product innovation. This study contributes to the sustainable finance literature by empirically validating the mediating roles of green finance and innovation in shaping banks' environmental performance. Based on these insights, the study proposes several recommendations to enhance green banking in Vietnam.