In this taxonomic revision of Dumasia (Fabaceae), eight species, two subspecies, and one variety are recognized. Two new combinations, D. villosa DC. subsp. leiocarpa (Benth.) B. Pan & X.Y. Zhu and D. yunnanensis Y.T. Wei & S.K. Lee var. arunachalensis (S.V. Predeep & M.P. Nayar) B. Pan & X.Y. Zhu are proposed. Four names are reduced to synonyms, and six lectotypes are designated. Chromosome numbers of D. forrestii Diels, D. hirsuta Craib, and D. yunnanensis Y.T. Wei & S.K. Lee are reported for the first time (2n = 20). Descriptions, illustrations, distribution maps, chromosome numbers, ecology, phenology, and a key to all taxa are provided.