This paper examines key determinants and the effect of country-of-origin on customer’s purchase intention of functional food and dietary supplement product in Vietnam. Exploratory study was identified to evaluate personal and social factors on customer’s buying behavior. Twenty-eight reflective constructs were adapted from literature and designed by using a seven-point Likert scale to facilitate measurement. By using non-probability convenience sampling, data was collected from a survey of 242 Vietnamese who have experienced in buying functional and supplement food. This paper employed partial least square structural equation modeling (PLS-SEM) as a technique employed to analyze the measurement and structural models. The findings provide evidence that social prestige customer perceives and their positive attitude toward functional food which are main factors influencing on consumers’ purchase intention. Customer’s perceived prestige plays an important role in decision-making process to purchase. The higher social prestige taken up in consumers’ mind, the higher consumers’ purchase intention is. Moreover, the more positive attitude customer holds toward functional food, the higher consumers’ purchase intention. The research results provide useful information in current understanding of what antecedents determine factors influencing customer’s intention to purchase functional food and lead to managerial implications for business strategies.