Environmental performance not only strengthens social legitimacy, but also leads to competitive advantage, because increases the productivity, and stimulates innovation in environmental performance activities. The purpose of this study is to investigate the role of women in the board of directors on the environmental performance of companies. To achieve this goal, the data of 160 companies listed on the Tehran Stock Exchange during the years 2016 to 2020 were collected and analyzed. The research method is logit regression and panel data. The results show that the presence of women on the board of directors of companies has increased the environmental performance. The presence of women on the board can increase the company's ability to create and absorb various resources (such as; knowledge, communication, reputation, and information) to perform the responsibilities of managers on behalf of shareholders. The combination of skills resulting from gender diversity on the board leads to the creation of the necessary expertise to focus on consulting, legitimacy, and communication channels, in addition to the above, increases the company's attention to complex environmental issues and leads Improves the environmental performance of companies. Therefore, our research provides valuable direction for those firms working to improve both their boards’ gender diversity and their environmental performance.