Corporate governance (CG) is a popular topic that gets more concerns today, especially infast developing countries. Numbers of projects and studies relating to CG and their effectson financial performance of companies have been done in many countries, but still this kindof topic is quite new in Vietnam.This paper tries to find out if there is any relationship between board size & composition,board activity, and ownership concentration and firm performances. Based on collectinginformation of listed companies in Vietnam, I use statistical analysis and quantitativemethod to get the paper’s objectives.Based on CG theory and the role of CG structures such as board of directors, ownershipstructure, and this paper also make a review on the compliance of listed companies with CGrules at Vietnamese market recently.Our empirical findings show that independent directors enhanced firm performance;inversely, the dual position of CEO and Chairman has a positive relation with firm value.Besides, age of director and the number of directors meeting play important roles in firmvalue. However, no significant impact of board size, board gender diversity, top tenshareholders concentration and levels of state ownership on firm performance. Lastly,regression model of market performance shows that the duality of CEO and Chairman andthe number of independent directors are significant impact on firm value.