Private-sector finance has been widely embraced as an important part of efforts to scale up resources for developing countries to respond to climate change. Yet there has been very little analysis of what private finance means for developing countries, and whether it will really deliver what is intended. This paper explores what historical patterns of investment reveal about the potential for the private sector to play a significant role in raising and delivering climate finance, specifically in the context of the adaptation needs of developing countries. It finds that private-sector finance is unevenly distributed among countries and among sectors, and it often does not match developing countries’ most pressing needs.