The genus Oxytropis L. (Fabaceae) comprises over 600 accepted species, ranking amongst the largest in the family. Nearly 100 Oxytropis taxa have been reported from Mongolia, spanning five subgenera and 20 sections in Mongolia. In this study, a new species, Oxytropis jamsranii Munkht. & Baasanm., from the Ikh Bogd Mountains in Mongolia, is described and illustrated. Based on morphological characteristics, it belongs to the section Xerobia. Although similar to O. leptophylla and O. sobolevskajae within the section, O. jamsranii is clearly distinguished by its indumentum, raceme structure, leaflet number and shape and corolla colour. The first occurrence of O. sobolevskajae — previously known only from the Republic of Tuva of Russia — in the flora of Mongolia is also reported here. Taxonomic nomenclature, morphological descriptions, distribution maps and field photographs for the new species and its two close relatives are provided.