A synopsis of the genus Rungia in Thailand is presented. The 14 species are listed together with a synoptic account of each species
and an identification key is provided. Rungia repens is selected as the type of Rungia. One species, Rungia brandisii is a new record
for Thailand. Lectotypes are selected for Rungia adnata, R. brandisii, R. diversibracteata, R. maculata, R. rivicola, R. subtilifolia
and R. tenuissima. A new combination, Rungia polyneura is made for Justicia polyneura which is found to belong within Rungia
based on morphological characters.