The idea of establishing an Islamic common currency has been proposed since 2003 as a strategy to enhance economic convergence and reduce the dependence of member states of the Organization of Islamic Cooperation (OIC) on the Western financial system. Despite the lack of concrete implementation, the proposal remains of significant theoretical and strategic importance. This study aims to assess the feasibility of forming an Islamic common currency among OIC members, using a mixed approach (comparative and descriptive–analytical) and drawing on the Eurozone experience and the theory of Optimum Currency Areas (OCA), examining the economic, institutional, and political dimensions of the idea. The findings indicate that an Islamic common currency could potentially reduce transaction costs, increase intra-regional trade (40–60%), and mitigate sanctions-related risks, particularly for Iran. However, economic heterogeneity (an 82% disparity in GDP per capita), high reliance on oil revenues (around 60%), and geopolitical rivalries among countries such as Iran, Saudi Arabia, and Turkey are major obstacles. Furthermore, the Eurozone crisis demonstrates that the absence of effective supervisory institutions and shock-adjustment mechanisms can lead to an unequal distribution of benefits between stronger and weaker economies. Therefore, a direct transition to a single Islamic currency is unrealistic, and its success requires a gradual, staged approach based on institutional convergence and complementary monetary arrangements, such as an Islamic settlement currency, which could reduce Iran’s dollar dependence and strengthen its position in the Islamic world economy.