Regional organisations play a central role in coordinating regional climate change adaptation responses across small island developing states, 58 countries that are particularly vulnerable to climate change and its impacts. The effectiveness of these organisations in coordinating adaptation efforts is underexplored in the academic literature, and this paper helps to fill the gap. By developing the Framework for Assessing Regional Organisations Coordinating Climate Change Adaptation, it qualitatively assesses the adaptation-related inputs, projects/programmes and outputs of the Caribbean Community Climate Change Centre, the Secretariat of the Pacific Community and the Secretariat of the Pacific Regional Environment Programme. This assessment is enriched by data gathered through interviews with national and regional climate change and development officials in the Caribbean and Pacific. It finds that regional organisations are more effective with respect to their adaptation-related inputs and outputs, but are less effective in coordinating adaptation projects/programmes. It recommends that, in addition to differentiating organisational mandates, regional organisations should focus on resolving the major climate-related information deficit issues, helping countries to develop ready to finance investment projects, building national-level capacities to adapt and supporting the creation of an enabling environment for climate change adaptation.