The environmental sustainability of businesses depends largely on employees’ creative environmental ideas and innovative solutions to environmental problems. This article analyzes how companies that want to improve their environmental performance can increase their employees’ willingness to eco-innovate. Results of an employee survey show that supportive behaviors from line managers significantly increase the probability that employees will try environmental initiatives. Even in firms that have sustainable development policies, line managers are less supportive when managing environmental issues compared to managing other business issues. Stated environmental policies may not have much of a direct influence on employees’ willingness to eco-innovate. This article shows how firms can encourage line managers to adopt behaviors that employees perceive to be supportive of environmental actions, and it indicates which behaviors and policies are most effective at supporting environmental innovations.