The Buyid dynasty, which came to power in Baghdad as a Shia-controlled government during the 4th and 5th centuries AH, had profound impacts on the political and social conditions of their era. This paper conducts a comparative analysis of the policies and behaviors of the Buyids in relation to the Abbasid caliphs and Shia communities. The findings indicate that following the fall of the Sassanids, the Umayyad and Abbasid caliphates governed Iran, and Sunni Islam was established as the predominant religion. With the rise of the Buyid rule, the authority of the Abbasid caliphs was diminished, relegating their role to symbolic activities. Through consolidating their power, the Buyids sought to reduce religious conflicts and exert control over border regions. This regime reinforced Shia identity in Baghdad by conducting Shia ceremonies and developing sacred sites. Additionally, by adopting a policy of tolerance towards other denominations, they maintained social stability. The relationship between the Buyids and the Abbasid caliphs was also complex; by preserving the appearance of the Abbasid caliphate and restricting the caliphs’ powers, the Buyids used the caliphate as a tool to legitimize their rule. However, religious tensions between Sunnis and Shia increased due to radical behaviors and sectarian prejudices. The Buyids endeavored to sustain social stability by controlling religious fanaticism and preventing social provocations. This study employs a descriptive-analytical methodology, and its conclusion demonstrates that the policies of the Buyids had profound effects on the political and religious structures of the period, leading to fundamental changes in the Abbasid caliphate system.