In this paper, we investigate the relationship between gender and environmental sustainability. Based on a sample of 296 firms, drawn from the population of US publicly traded firms over a five‐year period, we empirically test whether firms that have (1) more gender diverse boards of directors and (2) more policies and practices that enable or reinforce gender diversity throughout the organization, adopted more environmentally responsible policies and practices. We find that both ‘demographic’ and ‘structural’ gender diversity are significant predictors of a firm's environmental sustainability initiatives. Our findings show gender diversity is a sustainability issue as well. Copyright © 2016 John Wiley & Sons, Ltd and ERP Environment.