Gender diversity on the board of directors can influence companies’ voluntary disclosure such as their environmental, social and governance disclosure (ESG). A growing body of literature suggests that most of the work of the board occurs in committees, which are smaller working groups within the board. In a smaller working group, even a small number of women can represent a higher proportion of the group. Therefore, the influence of gender diversity on a board’s decisions can be more prevalent in committees, since women’s ideas and opinions can have more of an impact in smaller working groups. By being on committees, women have the chance to actively contribute to board tasks and decisions. This study investigates the relationship between the gender diversity of the board and its main committees and the ESG disclosure of Canadian-listed companies. The results indicate a positive and significant relationship between female representation on the board and committees and ESG disclosure. Using a structural equation model, the results suggest that there is a joint influence on ESG disclosure of gender diversity at the board level and at the committee. level. In addition, the study demonstrates that for ESG disclosure, the influence of female representation on committees is higher than the influence of female representation on the board. This study shows that by being on committees, women can better contribute to board decisions and that the influence of board gender diversity is not limited to female representation on the board but also comes from female representation on committees.