The study investigates the relationship between firm attributes and environmental accounting reporting among listed oil and gas companies in Nigeria. Using secondary data extracted from annual reports of eleven firms between 2011 and 2020, environmental disclosure was measured through a 20-item Environmental Reporting Index (ERI). Firm size, leverage, profitability, and listing age were adopted as explanatory variables, while multiple regression analysis tested the hypotheses at a 5% significance level. The results show that the average ERI score of 12.7 out of 20 indicates a moderate but inconsistent level of disclosure among the firms studied. Empirical evidence revealed that firm size and leverage are significant positive predictors of environmental reporting, while profitability and listing age, though positive, are statistically insignificant. The model explains 62% of the variation in environmental disclosure, confirming the joint influence of firm attributes on reporting practices. The study concludes that larger and highly leveraged firms are more likely to disclose environmental information, supporting stakeholder and signaling theories, while profitability and firm maturity do not play decisive roles. It recommends strengthening regulatory frameworks, expanding disclosure requirements across industries, and promoting capacity building to enhance environmental accountability in Nigeria.