The activities of nonstate actors are proliferating and their inclusion in global climate governance has increased. As a substantial amount of climate actions are being carried out by nonstate actors, certain major powers have strengthened their engagement under the framework of existing multilateral environmental agreements. This article offers two contributions. First, it outlines the European Union’s (EU) contemporary agenda regarding climate change and the support to non-EU countries and nonstate actors who engage in climate actions. Second, it analyses the assistance it provides to nonstate actors from developing countries through various foreign policy tools. In conclusion, political recognition, as well as financial and technical support from the EU to nonstate actors could help to curb CO2 emissions. These cooperation schemes have the potential to foster the proliferation of climate solutions and promote effective climate governance. Yet nonstate actors require further strengthening for adequate and far-reaching actions to limit climate change.