The main disagreement between Sunni and Shia Muslims is over the rightful successor to the Prophet Muhammad. Sunnis believe that the successor should be elected by the Muslim community, while Shias believe that the successor should come from the Prophet Muhammad's family, specifically through his cousin and son-in-law, Ali. This disagreement led to the split between the two sects shortly after the death of the Prophet Muhammad. Additionally, there are differences in the interpretation of Islamic law and traditions between the two sects.
