A new species of gekkonid, Hemiphyllodactylus chiangmaiensis sp. nov., from northwestern Thailand is separated from all other species of Hemiphyllodactylus by a set of features including: a maximum SVL of 41.2 mm; 8–12 chin scales extending transversely from unions of second and third infralabials and posterior margin of mental; lamellar formula on hand 3–3–3–3 or 3–4–3–3; lamellar formula on foot 3–3–3–3 or 3–4–4–4; continuous precloacal and femoral pores; a unique dorsal color pattern; and caecum and oviducts pigmented. These characters place this species in the speciose H. typus group. Hemiphyllodactylus chiangmaiensis sp. nov. fills a biogeographical hiatus in the distribution of this genus across northern Indochina.

Keywords: Gekkonidae, Hemiphyllodactylus, Hemiphyllodactylus chiangmaiensis sp. nov., Thailand, Chiang Mai, new species