The Biodiversity Expenditure Review (BER) under UNDP’s BIOFIN establishes Cambodia’s 2018 baseline of biodiversity spending aligned with the NBSAP. It defines what counts as biodiversity expenditure, maps public and private sources, channels and instruments, and assesses government revenues and funds to identify opportunities to mobilize finance. The BER answers how spending is defined, how much is allocated across NBSAP themes and key sectors, and the scale of private investment. Findings highlight main financing sources, where expenditures could be re-aligned, allocation/absorption bottlenecks, and practical next steps. While national revenues have grown under PFM reforms, biodiversity-linked revenues (e.g., timber, rubber, concessions) remain modest—pointing to avenues for stronger, targeted resource mobilization.