While studies show that organizational diversity is beneficial to their practice of environmental sustainability, we know very little about the effect that the gender of an individual director can have on sustainability practice. In this empirical paper, we employ a micro‐foundational approach to examine whether the number of women on an organization's board of directors has a direct effect on its attitude towards environmental sustainability, regardless of the national culture in which the organization is located. Culture in this study is measured through grammatical gender marking, a unique approach to measuring women‐oriented cultural effects. Previous studies show that certain cultures have more gender roles than others do, which in turn affect general and organizational behavior in that society. Grammatical gender marking enables us to study the impact of gender of the individual director on the organization's attitude towards environmental sustainability across cultures, by empirically examining data from 71 countries, sampling 4500 organizations for multiple years and industries. Our findings show that organizations become significantly more proactive in environmental sustainability with the appointment of even one woman to the board of directors, regardless of the local culture. We further show that the organization's level of disclosure regarding its sustainability activities increases with the number of women on the board of directors. Our data also show a significantly negative relationship between various gender‐based language indices and the presence of women on the board of directors. In cultures defined by a language that has clear grammatical gender markings, there is a tendency to appoint fewer women to boards of directors, thereby influencing indirectly the organization's attitude towards environmental sustainability.