In the Southwestern border region of Vietnam, Theravada Buddhism has long been the spiritual backbone and cultural bedrock of the ethnic Khmer community, shaping religious practice, interpersonal relations, family life, and collective identity. The article discusses the dialectical mechanism of influence and maintenance of the moral views of the Khmer people in Tri Ton commune, An Giang province through Theravada Buddhism in the setting of a high concentration of Khmer people, 14 Theravada pagodas and the existence of multi-ethnic groups including Kinh and Hoa. The study uses theoretical perspectives of dialectical and historical materialism, ethical philosophy and sociology of religion and employs a fully mixed-method research design. It uses structured questionnaire survey with 200 randomly selected lay residents, semi-structured in-depth interviews with 12 key informants comprising Buddhist monks, temple leaders (Achar), community elders and parents, and direct participant observation during religious ceremonies and communal work activities. The results show that Theravada Buddhist teachings about Kamma and personal responsibility, compassion and non-harm, the Five Precepts, and the path of self-purification are not abstract or imposed from the outside. Instead, they are mediated, interpreted, and continuously reinforced through four interlocking institutional channels: the pagoda (wat), the monastic order (Sangha), the extended family, and traditional hamlet–village structures (phum–srok). Through a four-stage cycle of reception, institutional mediation, internalization, and lived embodiment, these ethical principles are transformed from shared teachings into deeply held personal convictions and consistent patterns of daily behavior.Despite mounting pressures from out-migration, economic restructuring, and generational change, the study reveals remarkably high normative consensus across all measured dimensions, suggesting that Theravada Buddhist ethics remain a vital and resilient spiritual anchor. The research concludes by affirming the decisive role of community-based institutions in moral transmission and offers practical implications for cultural preservation, social cohesion, and inclusive development in Vietnam’s multi-ethnic borderlands.