Rungia flaviflora (Acanthaceae), a new species from Southeast Yunnan, China, is described and illustrated. The new species resembles R. burmanica in shape and texture of leaf, as well as bract and corolla shape, but differs in its growth habit, plant size, cystolith shape, spike length, bract margin, and corolla colour. Among known taxa in the genus, this species is also distinctive in having tricolporate pollen grains and a chromosome number of 22. Information on pollen morphology, chromosome number, and karyotype is given, and a line drawing, color plate, and distribution map of the new species are also provided. This new species was previously misidentified as R. monetaria, which is restricted to Vietnam and does not occur in China.