This study aimed to measure the impact of oil rent on environmental degradation in the Libyan economy during the period (1990–2021), using the Autoregressive Distributed Lag (ARDL) methodology to test the relationship between oil rent (OILR) and carbon dioxide emissions (CO2) as one of the most important indicators of environmental pollution. The results revealed the existence of a long-run equilibrium relationship between the two variables, showing that an increase in oil rent leads to higher emission levels, reflecting the Libyan economy’s reliance on energy-intensive and environmentally inefficient activities. The findings also indicated that 57% of short-run disequilibria are corrected in the following year, which restores the relationship toward long-run equilibrium. These results suggest that Libya’s rentier economic model is a direct cause of mounting environmental pressures, which necessitates reconsidering economic and environmental policies to achieve sustainable development.............. Keywords:.......... Oil Rent, Environmental Degradation, Carbon Dioxide Emissions, Libyan Economy