Financial support for mitigation and adaptation actions in developing countries is at the core of the climate negotiations under the United Nations Framework Convention on Climate Change (UNFCCC). This is due to the legal obligations created by the Convention itself and the critical role of finance in enabling developing countries to take ambitious climate action. This policy brief highlights that the Green Climate Fund (GCF) should anticipate and prepare to act upon issues that are likely to emerge in the fifth review of the UNFCCC’s financial mechanism, with a view to securing favourable results. These issues include: building on the best features of the existing funds and learning from their shortcomings; clarifying roles and responsibilities between the GCF and the UNFCCC’s Conference of the Parties (CoP) to avoid varying interpretations; and anticipating the possibility that the SCF will initiate an independent review of the GCF.