Oligoaeschna sirindhornae sp. nov. is described from a male from Sakaerat Silvicultural Research Station, Nakhon Ratchasima Province in Thailand. It is the only known Oligoaeschna species recorded from Thailand since Oligoaeschna pramoti (Yeh, 2000) and Oligoaeschna minuta (Hämäläinen & Pinratana, 1999) were transferred to the genus Sarasaeschna.
Keywords: Odonata, Anisoptera, Aeshnidae, Oligoaeschna, sirindhornae, new species, Thailand, Nakhon Ratchasima, Sakaerat.