This study investigates the validity of the Environmental Kuznets Curve (EKC) hypothesis for Nigeria over the period 1980–2022, using the Autoregressive Distributed Lag (ARDL) econometric model. The EKC hypothesis suggests that environmental degradation initially worsens with economic growth but improves after a certain income threshold is reached. The analysis incorporates key variables such as CO2 emissions, per capita income, oil rents, and urbanization. The findings reveal statistically significant evidence supporting the EKC hypothesis in Nigeria, with a positive coefficient for per capita income and a negative coefficient for its square, indicating that economic growth initially increases CO2 emissions but reduces them after reaching a turning point. Additionally, oil rents are found to exacerbate environmental pollution, while urbanization contributes to environmental improvements. Based on these results, the study recommends stricter environmental regulations in key polluting industries, the promotion of advanced low-emission technologies, and urban planning policies aimed at developing eco-friendly cities. Limitations include the focus on CO2 emissions and the exclusion of other environmental factors such as deforestation and water pollution. Future research should broaden the range of environmental indicators and account for external shocks, such as oil price fluctuations and technological changes, to provide a more comprehensive understanding of Nigeria’s environmental dynamics.