A scincid lizard recently collected in Boloven Highlands, South Laos, proved to be the second known specimen of Siaphos tridigitus Bourret, 1939. This species was previously known only from its holotype obtained at Bach Ma, central Vietnam. The new specimen is described and depicted, and compared with the holotype. Relationships of this species are discussed. It is tentatively placed in the genus Sphenomorphus Fitzinger, 1843.
Reptilia, Lacertilia, Scincidae, Siaphos tridigitus, Sphenomorphus, Laos, Vietnam, morphology.