Vietnam is a rapidly developing country associated with changes in socio-economic activities, especially both public and private services. The service industry is making a practical contribution to economic growth and is gaining a great position. To help a society develop harmoniously, the economy must satisfy people's ability to access services, especially basic services such as education, healthcare, legality, transportation, security and safety. The aims of the study are to estimate factors affecting legal service quality, and based on the survey in three provinces in Vietnam: Lam Dong, Dak Lak, Gia Lai and through quantitative analysis, the research results show that there are five factors that positively affect service quality, which are: (1) government; (2) head of the unit; ⁠(3) influencer; (4) opinions of people around; and (5) organizations and individuals providing services. The research results also discuss some solutions to increase service quality and sustainable development of Vietnam in the coming time.