The Ctenopelmatinae is one of the least explored groups of Ichneumonidae in South East Asia. We describe and illustrate an enigmatic new genus, Thaictenopelma Ranjith, Reshchikov & Quicke with the type species, T. splendida Ranjith, Reshchikov & Quicke, sp. nov., from a moderately high altitude site in northern Thailand. The new genus shows a unique set of morphological characters that distinguishes it from all other ctenopelmatine genera. The presence of a pair of complete latero-median as well as complete dorso-lateral carinae on the T2 are considered autapomorphic characters of the new genus. Affinities of the new genus within the Ctenopelmatinae are discussed and a note on the taxonomic placement is provided.