Most of the controversies surrounding how to structure climate change mitigation and adaptation – including financing, what counts as action, and how to measure progress against uncertain goals – have technological change as an underlying assumption. Technological transformation is at the heart of mitigation in the energy system, and technological change (cultivars and management) will be a prime contributor to mitigation and adaptation in agriculture and water. Therefore, the issue of governing the diffusion of GEC- related technology is critically important. The standard analyses that assume we just need to “get the prices right” are insufficient in a world where markets are at best imperfect and equitable well-being is as much a goal as efficiency. Our research examines the ways in technological change is guided by such governance factors as governments (regulation and policy), firms with existing expertise and infrastructure, international and national needs for security, innovation networks, and leadership. We will illustrate the determinative nature of these governance factors through case studies of two major energy technologies – nuclear power and biofuels – in three countries – Brazil, Sweden, and the United States. Primary data comes from interviews with policymakers and firm managers who have been involved in these changes in the three countries. Open-ended and structured questions about a range of driving or enabling factors allow us to establish one or more configurations of factors that can inform the governance of future technological change related to mitigation and serve as the basis for further research into technological change related to adaptation.