Knowledge plays an important role for the development of any economy, any business especially within the law profession which requires profound knowledge. Knowledge sharing behaviors may improve the performance of the work. The proposed study of this paper is conducted among 398 lawyers in Vietnam to assess the factors affecting the knowledge sharing behavior of lawyers. After analyzing data based on Smart PLS software, the results show that the knowledge sharing behavior of lawyers in Vietnam contributes to their jobs except for the development process according to the planned behavioral theory. At the same time, the paper examines the mediating role of behavioral intent for the relationship between attitude and knowledge-sharing behavior which is statistically significant. However, the level of information use does not have any statistically significant role for the relationship between intentional behavior and knowledge sharing behavior of lawyers in Vietnam.