This study on Mahāsammata Model of Kingship in Mrauk U Period from the 15th to 18th centuries attempts to demonstrate how the kings of Mrauk U or royal officials tried to claim this legitimating model of kingship and how they accepted this model of kingship and under what conditions the legitimate order of this model was lost. Vital to the adaptation of Mahāsammata model of kingship in the Mrauk U period is the claim that Mrauk U’s rulers were direct lineal descendants of the first Buddhist king of the world, Mahāsammata and thence the clan of Gotama Buddha, Sākiya clan. This ideological model of kingship has a recognizable effect on the political stability of Mrauk U kingdom. While the Mahāsammata model of kingship performed as a belief of legitimizing kingship within the arena of royal court, the kings of Mrauk U tried to perform the related models of Mahāsammata, the ideal models of Buddhist kingship as dhammarāja and a cakkavatti. However, the conditions that fail to maintain the Mahāsammata model of kingship saw the weakening of the other related models of kingship, which eventually led to the decline of the kingdom.