Since its establishment, the Global Environment Facility (GEF) has disbursed over $24 billion, with partners committing an additional $138 billion in cofinancing for projects aimed at generating global environmental and climate change adaptation benefits. The GEF’s updated cofinancing policy (2018) underscores the role of cofinancing in enhancing project effectiveness, sustainability, and the generation of broader environmental benefits, while also fostering partnerships. This evaluation examines the GEF approach to cofinancing, compares the GEF strategy with that of other multilateral organizations, and assesses the overall effectiveness of cofinancing in achieving the expected benefits. It also seeks to understand how the GEF and its partners raise and manage cofinancing, as well as to identify factors influencing cofinancing commitments and their realization. The evaluation found that the GEF's approach to cofinancing is ambitious and flexible, helping it raise cofinancing from diverse sources and attract high levels of funding. Cofinancing enhances the scale of activities, their effectiveness, and their sustainability by fostering national ownership. However, challenges include the realization of commitments, credible reporting, and difficulties in ensuring proportionality in project management costs.