The relationship between ownership structure and environmental performance has long been a subject of debate in the literature. This study investigates the effects of various ownership characteristics on environmental performance within the energy sector firms of G20 countries. We hypothesize that ownership concentration, as well as institutional, government, and foreign ownership, are significantly associated with firms' environmental performance. Using a dataset of energy sector companies from 2018 to 2022, collected from the Thomson Reuters Eikon database, we employ multiple linear regression analysis to test our hypotheses. The results reveal that foreign ownership is significantly and positively related to environmental performance. In contrast, institutional ownership has a significant negative effect on environmental performance. We also find that the developed G20 countries have a stronger influence on the overall sample results compared to the developing G20 countries. These findings contribute to the ongoing debate on the role of ownership structure in shaping corporate environmental practices, with important implications for policymakers, regulators, and energy companies operating within the G20 context.