We describe a new species of wolf snake of the genus Lycodon from the Cardamom Mountains of southwestern Cambodia. The new species differs from other species of Lycodon in Southeast Asia in the following combination of characteristics: dorsal scales feebly keeled, in 17 rows at midbody; 12 well defined, broad white bands across black body and six across the tail; presence of both a single preocular and a loreal, causing absence of prefrontal-eye contact; three postoculars, two anterior temporals. Visually, the new species is most similar to Lycodon subcinctus, and specimens labeled as L. subcinctus from eastern Thailand and elsewhere in Cambodia should be checked against the diagnosis of the new species.