The Ahier Cham ethnic community, which primarily resides in Ninh Thuan and Binh Thuan, is the most numerous of the Cham communities that practice other religions. They are Brahmanic. Despite its early introduction and the loss of numerous cultural legacies, Brahmanism has been heavily “localized.” The study examines the evolution of Brahmanism in the Ahier Cham ethnic community in Ninh Thuan and Binh Thuan, Vietnam, based on ancient Brahmanism teachings in life-cycle rituals. It demonstrates that many Brahmanism birth and adulthood rituals have been replaced by indigenous customs in the Ahier Cham community. The patriarchal beliefs of Brahmanism have been radically altered by the matriarchal system. Although there are some traces of Brahmanism, such as the tradition of forbidding the consummation of the wedding night for three nights, wedding rites are overseen by the matriarchal system. The customs that most closely adhere to Brahmanism are funerals, particularly the idea of "reincarnation and liberation.” With the Creator portrayed as the “Mother of the land Po Inư Nagar” and stringent laws governing matrimony and Kut worship, Brahmanism was? “Chamized—localized” into a regional religion. Additionally, studies reveal that indigenous customs have developed alongside external influences, resulting in distinctive Cham cultural nuance.