Inheriting and developing the Functioning Tourism System (FTS) model of Gunn (Gunn, 1988; Clare, Gunn, & Turgut Var, 2002), this study assessed the potential of cultural heritage tourism (CHT) in Vietnam. The research results show that the current CHT activities in Vietnam are below the potential. In addition, the study shows that the heritage tourism potential is based on the elements that constitute the tourism system according to the FTS model as destination/attractions, transportation, information, promotion, system of services, travel needs of the community and especially safety and security not only in the area of the tourist destination but also in the whole country. These elements are closely linked with each other and without one of these elements, the tourism system cannot exist and develop. The study also clarifies that the more complete the heritage tourism system, the greater the potential for CHT.