Scholarship examining the highly successful ozone negotiations is rare today, as lessons derived from them do not seem to have produced comparable success in climate negotiations. This article argues that there is a “missing piece” critical to understanding ozone negotiation success. I draw on path dependency and feedback literature as well as detailed historical research into the ozone negotiation process to propose a coherent feedback mechanism I refer to as the “green spiral.” In a green spiral, an iterative interaction between negotiation outcomes and changes to the sticky, internal material interests of industry works to make more stringent regulation feasible in subsequent negotiating rounds. Such dynamics offer a consistent explanation for the overall success of the ozone negotiations as well as the timing and nature of individual countries’ shifts in negotiating position and regulatory behavior over time. Understanding environmental negotiation through this lens offers insight into how outcomes of climate and other environmental negotiations might be improved.