Employee green behavior research has not focused on its holistic examination from the perspective of the environmental theory of planned behavior and bridging of green intention-behavior gap. This study examines the impact of employee green attitude, green subjective norms, and green perceived behavioral control on both required (in-role) and voluntary (extra-role) employee green behavior through green behavioral intention. The moderating role of perceived organizational support toward the environment has also been examined in the intention-behavior relationship. Multisource data was collected from 720 employees and their 72 supervisors in three time-lags and was analyzed through structural equation modeling. Results show that employee green attitude, green subjective norm, and green perceived behavioral control positively influence employees' both required and voluntary green behavior indirectly through their green behavioral intention. Also, perceived organizational support toward the environment strengthens the positive effect of employee green behavioral intention on their required and voluntary green behavior.