Bulbophyllum xuansonii belonging to section Brachystachyae, discovered in Ninh Binh and Son La provinces is described here as a new species for science. This species is similar to B. xylophyllum and B. gracilipes but can be easily distinguished by the smaller habit and shape of tepals and stelidia. Additionally, B. gracilipes found in Lam Dong Province is reported as the species newly recorded for the flora of Vietnam. The paper provides analytical photos and data on phenology, ecology, and distribution of studied species. Morphological characters of the new species and similar species are shortly discussed. The key for identification of species of B. sect. Brachystachyae in Vietnam is also included.