The promise of climate finance has been a fundamental challenge within the UNFCCC regime since its inception. While the Parties agreed on a Financial Mechanism, and that developed countries would provide ‘new and additional resources’, developed and developing countries have often been at odds over this commitment, and more fundamentally, what constitutes ‘climate finance’, how much should be provided, and whether there has been adequate balance between mitigation and adaptation. Just when Paris seemed to show signs of momentum toward climate finance targets, the new US Administration reversed course on the prior administration’s commitment to the Green Climate Fund. This article looks at the possible impacts of the US decision on climate finance, including the efforts of other countries and international organizations to address the potential funding gap.