A taxonomic study of the genus Chloris Sw. in Thailand is presented. Five Chloris species are recognised in Thailand; namely, C. barbata Sw.,C. gayana Kunth, C. Montana Roxb., C. pycnothrix Trin., and C. virgata Sw. Chlorisvirgata is firstly reported for Thailand, where as C. punctata (R. Br.) Jannink and C. radiata (L.) Sw. may have been misidentified in previous Thai reports. Type specimen at K is lectotypified here for C. gayana. Key to the species is given for distinguishing the species. Descriptions, distributional and ecological data, vernacular names, and notes on each species are provided.