The first known occurrence of Petinomys setosus in Lao People's Democratic Republic (PDR) was recorded from a single specimen collected at Na Mouang village in Vientiane province, which is approximately 240 km from its nearest known distribution in northwestern Thailand. We describe the morphological and cranial features of this specimen and discuss its occurrence in Lao PDR. The focal Laos specimen is similar in pelage color to those from northwestern Thailand, particularly on the dorsal and ventral surfaces of the body, gliding membrane, face, and tail. The cranio-dental characters (bullae and dental patterns) are also similar.