The study is conducted to analyze factors affecting the transparency of corporate social responsibility (CSR) of companies listed in the Vietnamese stock market. Panel data is hand-collected from 323 non-financial companies listed on the Ho Chi Minh City Stock Exchange (HOSE) and Hanoi (HNX) in the period of 2013 and 2017. Tobit regression results show that company size, business profit, operation time, the percentage of non-executive directors and the ownership of foreign shareholders positively influence on CSR disclosure of listed companies. In addition, financial leverage, board size and the percentage of state ownership negatively influence on their CSR disclosure. Some policy implications are also proposed to improve CSR disclosure of Vietnamese listed companies such as reducing the debt ratio of companies, increasing the level of independent member in the board, separating between CEO and chairman positions, minimizing the number of board members in the board, reducing the state ownership and increasing foreign ownership.