Abstarct: The purpose of the current research is to evaluate the energy efficiency and environmental efficiency in OPEC member countries during the years 2015 to 2019 with the method of data envelopment analysis and using Lingo software.In this research, the amount of energy and environmental efficiency as well as the amount of energy waste and pollutants in OPEC countries were calculated. baxsed on the obtained results, the energy efficiency of most of the OPEC member countries, especially the countries of the Persian Gulf region, have had a good performance. The countries of Guinea, Gabon, Iraq, Kuwait, Libya and the United Arab Emirates achieved full energy efficiency in all the years studied.Congo, with an average energy efficiency below one, reached full efficiency during the studied years.Others, such as Algeria and Iran, followed by Saudi Arabia, were facing a decrease in energy efficiency.In the study of environmental efficiency, it was found that the countries of Algeria and Congo have faced a decrease in efficiency. In contrast, the countries of Libya, Guinea and the United Arab Emirates achieved ideal environmental efficiency. The countries of Algeria, Iran and Saudi Arabia have the most waste in both energy and environmental fields. Especially Iran, which shows the most wastage in both fields among the studied countries. Despite zero energy waste, Iraq has a high environmental waste.Countries with lower efficiency have consistently faced increased energy waste and increased emissions. This research also provides suggestions for OPEC member countries to increase their efficiency and productivity. Proposals include modernization of energy infrastructure, use of renewable resources and upgrading of energy transmission systems. Also, it is necessary to identify weak points and causes of energy waste and strengthen monitoring systems to monitor performance.