This study examines the relationship between green accounting practices and environmental sustainability of quoted oil and gas companies in Nigeria from 2018 to 2024. Using a quantitative research design with secondary data obtained from company annual reports, sustainability disclosures, and financial statements, the study analyzed environmental costs, corporate social responsibility (CSR) expenditure, and Environmental Disclosure Index (EDI) to assess their impact on profitability. Descriptive statistics, correlation, and regression analyses were applied to test the hypotheses. Findings indicate that companies with higher environmental investments, such as TotalEnergies and Seplat, achieved higher EDI scores and improved profit margins. Correlation results show strong positive relationships between environmental costs and profitability (r = 0.79), CSR expenditure and sustainability disclosure (r = 0.85), and EDI and profit after tax (r = 0.82). Regression analysis further confirms that green accounting practices significantly predict profitability, suggesting that environmental stewardship aligns with corporate financial objectives. The study concludes that green accounting serves as both a compliance and strategic tool, enhancing corporate sustainability, stakeholder trust, and long-term financial performance. These findings offer practical insights for policymakers, managers, and investors seeking to integrate sustainable practices into business operations.