The study compares six issues concerning religious belief and practices in four local Muslim groups in Ayuthaya Province. The six issues include perspectives toward the prophet-like practices, perspectives and treatments toward leaders, methods of blessing requests, funeral rites, speeches before Friday prayer, and celebration of the birth of the Prophet. It is found that every group has the same faith toward its religious principles and teachings. Differences are minor practical details derived from their individual leaders. Adherence to their religious leaders, acceptance of local cultures, and their historical background since the Ayuthaya Period are the main factors influencing their religious interpretations in integrating with their local cultures. As a consequence, there are belief groups with unique characteristics that have been maintained in the pluralistic society of Ayuthaya.