One of the issues that have gained a lot of attention in recent years is the board gender diversity. Many researchers believe that gender diversity in the board reinforces corporate social responsibility and on the other hand, gender diversity is one of the signs and effects of corporate social responsibility in the board, so there is a mutual relationship between board gender diversity and corporate social responsibility that has not been noticed up to this time. Our study fills this gap in literature by using the Simultaneous equations system. We use data from ۱۱۰ companies listed in the Tehran Stock Exchange during the ۲۰۱۲ to ۲۰۱۷ period. The results indicate that board gender diversity and corporate social responsibility have a positive and significant effect on each other. As a result, companies can improve their social responsibility by increasing gender diversity in the board, and on the other hand to prove their social responsibility, it is better to use women on the board.