This thesis examines the role of foreign state actors in the events leading to the overthrow of Bashar al-Assad's regime by Hay'at Tahrir al-Sham (HTS) in December 2024. The study focuses on the involvement of key external actors such as Turkey, Russia, Israel, Iran or the United States, analyzing their motivations and strategic behavior before, during, and after the regime change. The thesis aims to examine the nature of influence each foreign actor may have had on HTS's success in overthrowing the Assad government and to assess how competing external interests shaped the outcome of Syria's political transformation. The research will investigate the contribution of each selected state actor to the dynamics and final result of the regime change.