Abstract
This paper describes a new species of the millipede genus Streptogonopus Attems, 1914, Streptogonopus montanus sp. n. from Vietnam, the first record of Streptogonopus in Vietnam. The new species is characterised by the solenophore completely sheathing the solenomere, both coiled twice, and the solenophore with a small spine at its middle. The species was found at ca. 1,800-2,100 m on Ngoc Linh Mountain. This first record for the genus in the Indochina peninsula has expanded its distributional range to the easternmost part of Southeast Asian mainland. An identification key to Streptogonopus species is also provided.