In this article, the future trend of energy demand in Iran is analyzed using a long-range energy alternatives planning system (LEAP) model. First, the structure of Iran’s energy consumption and its historical trend are evaluated. Then the key assumptions of a LEAP model are defined, which comprise different economic growth, population growth, and urban settlement perspectives in combination with several assumptions on energy-saving policy rules. These assumptions are categorized into three different scenarios: reference, high, and low. Results imply an ever-growing demand in all three scenarios, and the ratio of final energy demand in the year 2041 to that of 2010 in High, Reference, and Low growth scenarios are projected to be 2.24, 1.8, and 1.6, respectively. According to the reference scenario, if current trends of energy conservation continue, by the year 2041 the shares of natural gas, petroleum products, electricity, and renewable energy from Iran’s energy demand basket are predicted to be, respectively, 53%, 34%, 10%, and 3%. Results show that Iran has a large potential for energy conservation, and, according to the reference scenario, the implementation of currently adopted rules may reduce its final energy demand by 21%. Additionally, renewable solar energy will play a more prominent role in the implementation of energy conservation policy acts in Iran.