This paper adopts the meta-analysis technique to a sample of 29 empirical articles to investigate the relationship between the board of directors' characteristics and environmental disclosure. The paper also investigates whether the findings are moderated by differences in country-level factors, such as geographic location, rule of law, environmental policy stringency and the level of commitment to sustainable development goals, and differences in the measurement of environmental disclosure. The results reveal that board size, independence, gender diversity, environmental committee and board meetings significantly and positively influence environmental disclosure. In addition, the findings show that geographic location intervenes in the relationship between board size, independence, CEO duality and environmental disclosure. Finally, the relationship between board size, CEO duality, and environmental disclosure is moderated by the measurement of the dependent variable.