The rivalry between Iran and Saudi Arabia in the Middle East began during the Pahlavi era, but after the Islamic Revolution, the competition began to take on new dimensions due to the changing political system in Iran and its Shiite orientation. Competition and, of course, their relationships have always been influenced by domestic and environmental factors, and depending on the foreign policy of the two countries, their approach has been competitive, aggressive and sometimes cooperative. Since 2015, there have been developments in both the internal and external environment of the two countries that have undoubtedly influenced the two countries' competitions in the Middle East. From this point of view, the research question is what are the reasons for the regional competition between Iran and Saudi Arabia in the Middle East in the period 2015-2017? It is also hypothesized that domestic and regional developments have consolidated the "foreign policy of the Companion" approach in the two countries and that aligning the countries of the region with their own policies has been the top priority of foreign policy goals. Given Randall Schoeller's theory of equilibrium of interest, the hypothesis is tested that, as a result of the paper, the competition of the two countries to align with the policies of the Middle East, especially Qatar and Iraq, is a new form of competition between the two countries in the region. . Iran has gained the support of Turkey, Qatar, Syria and Iraq at this point, and Saudi Arabia has gained the support of Egypt, the United Arab Emirates and Bahrain, while the center of competition is increasingly moving to Iraq. The research method is also descriptive-analytical.