This study aims to analyze the nature of sectarian conflict and its impact on the stability of the Umayyad State during the period (41-132 AH / 661-750 AD). The study focuses on examining the relationship between Umayyad authority and major Islamic sects, particularly the Kharijites and Shia, and how these conflicts contributed to weakening the state and ultimately led to its fall. The study employs a historical analytical methodology to examine the events, policies, and revolts that shaped this critical period of Islamic history. The findings indicate that sectarian conflict, alongside tribal prejudice and discrimination against the Mawali, played a pivotal role in destabilizing the Umayyad state and paving the way for the Abbasid revolution. The study concludes that the Umayyads' failure to manage sectarian and ethnic diversity within the state was among the most important factors that led to its collapse.