Organizational slack seems to have an ambiguous relationship with corporate greening. On the one hand, excess resources can be used to experiment with new environmental innovations, or potential green market segments. On the other, excess resources can be used to build corporate buffers against pressures for environmental improvement, such as large corporate environmental departments or environmental lobbying activity, and resist changes to the core of the organization. This paper begins to resolve these conflicting arguments by broadening the debate on organizational slack and corporate greening. It builds on recent empirical studies of slack and corporate greening, and recognizes the many potential roles that different types of slack may play in a dynamic decision-making context. Using a theoretical framework suggested by Bourgeois (1981), the paper systematizes and draws lessons from examples of the roles of slack encountered in a recent series of 35 interviews within UK public limited companies. It concludes that future treatments of slack and environmental management should incorporate a more holistic view of slack, which recognizes its dynamic, complex and often contradictory effects on decision-making in organizations.