Throughout history, the relationship between the Islamic Republic of Iran and the Kingdom of Saudi Arabia has been dynamic and complex. These two Middle Eastern superpowers went from being allies to being enemies that are fighting for hegemony in the region after the Iranian Revolution. Ideological and religious reasons are usually used to explain the shift in their relationship.However,the complexity oftheirrelationship can notonly be described by them.This thesis aims to analyse changes that occurred in the relationship between Iran and Saudi Arabia through the lens of the role that leadership played in their relationship,focusing on the impact that public support has on decisions brought by leadership. Already existing literature that relates to this research is mainly focusing on democratic countries. Therefore,this thesis aims to show that public opinion is vital for the non-democratic Middle Eastern leadership of Iran and Saudi Arabia, as well. It will determine leadership decisions related to their mutual relationship, as well as relations they have with other foreign powers, such as the United States and Russia