Prorops Waterston is a small genus of the family Bethylidae (Hymenoptera) with just four species known worldwide: P. nasuta Waterston (cosmopolitan), P. petila Evans (Nearctic, Neotropical); P. obsoleta Evans (Neotropical); P. rakan Terayama (Palaearctic). A new species is recognized from the tropic rain forest of Cambodia. It is characterized from congeneric species by ‘the elongated median process on the lower part of frons and the flat-broad mandible downwardly developed’. The new species is described and illustrated with a key to world species of the genus Prorops.