Religiosity tends to influence the intention of human beings and ultimately impact the behavior of an individual. Vietnam is one of the attractive countries having a religiously diversified population. Historically, the idea has been made that religious attitude and religion impact an individual's behavior in shaping the act. The current research endeavored to examine international religious interactions, the intrinsic and extrinsic perspectives of religiosity, and how they influence individuals' pro-environmental intentions and behaviors across samples recruited from numerous religious groups in Vietnam. The data were analyzed using Smart PLS, and the results indicated that while inner religiosity strongly predicts pro-environmental behavior, external religiosity also considerably predicts pro-environmental intention and behavior. Both intrinsic religiosity and extrinsic religions advocate for environmental protection. Endogenous religions such as Cao Dai and Hoa Hao have absorbed the teachings of foreign religions such as Buddhism, Catholicism, and Taoism and expressed the idea of environmental protection in their teachings, which influenced believers' pro-environmental behavior.