Many scholars hold that trust is one of the key in searching for inter-firm cooperation. But there are few studies to investigate the antecedent of inter-firm trust. The aim of the research is to identify the main determinants of inter-firm trust in tourism region. With an empirical study of 262 enterprises in a tourism region in Vietnam, the study finds that characteristics of firms and its executives do significantly positively affect inter-firm trust. The result also reveals that communication and sharing information, using social network in inter-firm relationship will facilitate trust between partners. The result support the general thesis that executive can build and develop inter-firm trust based on its main determinants. The study provides both theoretical and practical implications.