The paper delineates the different factors and structures that played vital roles in the sectarianisation of the conflict in Syria. Following recent academic efforts to reconceptualise sectarianism as a process, signified as sectarianisation, the paper proposes a framework of what this process looks like by examining it within its own historical, socio-economic, and political particularities in order to fully grasp its complexity and pervasiveness. The paper aims to demonstrate how the rhetoric and practices of the Assad regime, GCC states, Turkey and Iran contributed to the articulation and reification of ethno-sectarian rationalities and polarisations, albeit for their own political benefits, while refraining from disregarding individual agencies where they exist.