This thesis examines the role of the Green Climate Fund (GCF) in mobilizing private co-financing for climate mitigation and adaptation projects. Utilizing data from the GCF's Open Data portal, this study employs quantitative methods, including OLS regression and k-means clustering, to analyze factors influencing co-financing ratios and to identify distinct funding approaches within the GCF portfolio. Findings indicate that larger projects, particularly those focused on mitigation, tend to attract more co-financing. Moreover, financial instruments like equity and guarantees are notably effective in leveraging additional funds. The study also introduces a revised classification of funding windows into 3 distinct windows, highlighting the complexity of funding strategies necessary to address diverse project needs.