A new species of the dicroglossid frog genus Limnonectes is described from recent and historical museum specimens collected in central and southern Laos and northeastern Thailand. Limnonectes savan sp. nov. has males that bear a caruncle on top of the head, and most closely resembles L. dabanus from adjacent southern Vietnam and eastern Cambodia. However, the new species is readily distinguished from L. dabanus, and all other caruncle-bearing species of Limnonectes in mainland Southeast Asia, by its adult and larval morphology, mitochondrial DNA, and advertisement call. Its description brings the total number of caruncle-bearing species of Limnonectes to six.