This research provides for the first time a valuation of Veun Sai-Siem Pang National Park (VSSPNP) in Cambodia, which is a forest largely unfamiliar to the international community yet extremely significant in terms of biodiversity value. This study aimed to measure the monetary and non-monetary values of ecosystem services (ESS) of the forest. We estimated the total annual contribution of VSSPNP was US$129.84 million. Its primary contribution was air purification (US$56.21 million yr?1) followed by water storage (US$32.31 million yr?1), soil-erosion reduction (US$22.21 million yr?1), soil-fertility improvement (US$9.47million yr?1), carbon sequestration (US$7.87 million yr?1), provisioning services (US$1.76 million yr?1) and recreation (US$0.02 million yr?1). Traditionally the forest is used for timber and non-timber forest products, which in fact, composed only 1.36% of the total benefits. By analysing the published articles and reports on VSSPNP we determined the area had generated valuable academic and non-academic knowledge on natural resources. This forest had also created a diverse network among scientists and different organizations worldwide. We also identified the forest to be of cultural importance for indigenous people as they believe that their ancestors live inside the forest and protect them from vulnerabilities. Despite being part of one of the most important eco-regions in the world VSSPNP is undervalued and facing multiple threats such as illegal logging, poaching, population pressure and corruption. The current estimation of ESS would thus assist in the sustainable management of VSSPNP.