The relationship between board gender diversity and environmental disclosure has received considerable scholarly attention. However, the influence of national cultural dimensions on this relationship has not been extensively studied. Therefore, we investigate the data of multinational corporations (MNCs) to examine the relationship between board gender diversity and the environmental disclosure of MNCs, and the moderating effect of national culture. We find that (1) board gender diversity positively affects the environmental disclosure of MNCs, and (2) power distance, individualism, masculinity, and uncertainty avoidance negatively moderate this relationship and show how board members’ gender differences influence the board’s stakeholder management, as well as the effects of national cultures. We offer suggestions for policymakers to improve corporate environmental responsibility when formulating related policies by considering board gender diversity and national culture. We also provide suggestions for MNCs on ways to promote the positive effects of female directors and national cultural characteristics to maintain corporate reputation.