This paper reports a field study on the relationship between environmental management practices and organizational citizenship behaviour for the environment via exchange process (i.e. perceived superior support, perceived organizational support and employee commitment). Results from a survey conducted with 407 employees from several organizations suggest that employee is more likely to make extra environmental efforts if he/she perceives that the organization supports his/her supervisor by granting him/her the decision-making latitude and necessary resources to engage in pro-environmental behaviour.