The Assembly of Experts, in connection with the position and role of leadership in the Islamic Republic of Iran, holds significant importance. This assembly has three critical responsibilities: the selection, supervision, and potential dismissal of the Supreme Leader. Given its crucial duties related to leadership, it plays a decisive role in determining the destiny of the country. In this research, after examining the concept of leadership and its position within Iran's legal system, as well as theories regarding the selection of leadership, the study explores the Assembly of Experts and its functions concerning the institution of leadership. Subsequently, the existential philosophy and significance of this body in the selection and appointment of the Supreme Leader are thoroughly analyzed. The research methodology is descriptive-analytical, with data collection conducted through library-based methods. The aim of this study is to elucidate the issues related to the office of the Supreme Leader and the Assembly of Experts as outlined in the Iranian Constitution, based on various theories of appointment and selection. Additionally, it seeks to critically examine the actual mechanisms of the Assembly of Experts, its existential philosophy, and its role in the selection and appointment of the Supreme Leader.

Keywords: Leadership Selection Theory Appointment Assembly of Experts.