This paper will focus on the emergence of sectarianism as a framework for political mobilization as well as for the distribution of violence in the Syrian uprising. In order to do that, it will take into account the social actors involved in the uprising; the impact of the repressive strategies of the Ba’thist regime; and the use of Islamic vocabulary, symbols and spaces as a cultural idiom in the protests. The protests against Bashar al-Assad’s government started in early 2011. By April several cities and towns in Syria were in open rebellion against Ba’thist rule. The protesters were mainly urban and rural workers who became impoverished and politically marginalized during the decade of neo-liberal economic reforms fostered by Bashar al-Asad’s government. The use of religious (mainly Sunni Muslim) vocabulary, symbols and spaces in the protests was also a major feature of the Syrian uprising, reflecting the importance that religious nationalism acquired under Bashar al-Asad. The regime accused the protesters of being radical Salafis, to which the protesters responded with slogans and videos stressing their plural and non-sectarian character. However, the unequal distribution of violence by the government deepened the tensions and divisions between the Sunni population and other religious groups. As Sunni clerics, some with a decidedly sectarian discourse, tried to claim leadership roles in the uprising, many Christians and ‘Alawis refrained joining the protests and became increasingly supportive of the regime. These rising sectarian tensions gave political meaning to the religious identities present in Syrian society. The militarization of the uprising and its descent into civil war deepened this process with the rapidly growing importance of jihadi groups in the conflict. The appearance of the Islamic State (IS/ISIS/Daish), with its brutal use of violence against those who do not conform to its religious views, led to the consolidation of sectarianism as the main discursive and practical framework mobilized by all sides in the conflict. My analysis of the Syrian conflict allows us to understand how sectarianism was produced by the political mobilization and manipulation of differences and tensions between religious groups in Syrian society, rather than as a pre-existing element that informed the conflict from its beginning.