Various factors can contribute to political instability and hinder a society’s growth, prosperity, well-being, and national vitality. Historical, political, and social experience suggests that ethnic identity crises are one such factor. Given Iran’s multiethnic composition, encompassing Kurds, Arabs, Lurs, Azeris, Turkmens, Baluchis, and Persians, this study examines ethnic identity crises as a potential threat to political stability in the Islamic Republic of Iran. It first identifies the country’s ethnic groups and investigates whether they experience ethnic identity crises. It then examines whether, and to what extent, such crises have affected political stability. The study adopts a descriptive-analytical approach and analyzes library-based sources to test the hypothesis that ethnic identity crises are associated with political instability in the Islamic Republic of Iran. The findings indicate that ethnic identity crises have existed among some ethnic groups both before and after the Islamic Revolution and have contributed to political instability in the Islamic Republic at certain periods. Although explanations of political instability should avoid reductionism, ethnic identity crises can nevertheless be regarded as a significant contributing factor. The findings further suggest that addressing these crises through inclusive cultural and social policies and stronger interethnic dialogue can help reduce political tensions. Moreover, recognizing ethnic groups’ cultural and linguistic rights within the constitutional framework and implementing balanced regional development programs can foster national cohesion and sustainable political stability. The study concludes by emphasizing the need for a comprehensive, multidimensional approach to analyzing political instability in multiethnic countries.