We describe the first bovid fossils from the late middle Miocene (13.4–13.2 Ma) of the Mae Moh Basin of Northern Thailand, and assign the material to the new species Eotragus lampangensis sp. nov., Eotragus cf. lampangensis, and an indeterminate bovid. Our material represents the first report of Eotragus from Southeast Asia, thus greatly extending the geographic distribution of this genus across the Old World continents. While comparisons of the Southeast Asian specimens with abundant material of E. clavatus from Sansan (France) and E. aff. clavatus from Tarazona de Aragón (Spain) indicate a high degree of intraspecific variation within single species of Eotragus, the existence of two distinct taxa at Mae Moh remains a possibility. Based on previous carbon isotope studies of Mae Moh herbivore tooth enamel, Eotragus lampangensis sp. nov. foraged predominantly in an ecotone between grassland and forest.