To combat climate change without sacrificing long-term economic growth, innovation must be redirected toward green technologies. The authors review recent literature that has developed a directed technical change framework where innovation can be endogenously targeted either toward fossil-fuel enhancing technologies or clean energy sources (such as renewables). They provide empirical evidence of path dependence in firms’ choice between green and dirty innovation. They then draw implications of this path dependence for the design of environmental policy and for economic growth. In particular, they show that their framework has distinctive implications regarding unilateral environmental policies, international cooperation, the use of intermediate energy sources such as natural gas, and the role of civil society.