The adults, male genitalia, pupa, and larva of Topomyia (Topomyia) irianensis n. sp. from Irian Jaya, Indonesia, are described and illustrated. The new species is compared to closely related species, Topomyia dejesusi Baisas and Feliciano, 1953, and Topomyia argyropalpis Leicester, 1908. Topomyia (Suaymyia) papuensis Marks was recorded for the first time from Maluku and Irian Jaya. This is the first record of the genus Topomyia from Maluku and Irian Jaya, Indonesia.