Protomedetera gen. n. (Diptera: Dolichopodidae), a new genus of the subfamily Medeterinae, is described from the Oriental and Australasian realms based on four new species. Protomedetera singaporensis Grootaert & Tang, sp. n. is designated as type of the new genus. The genus is peculiar because of the small body size, the small globular first flagellomere (postpedicel), the simple male genitalia with indistinct or small epandrial lobe and half-hidden cercus. The following four new species are described and illustrated: P. biconvexa sp. n., P. biseta sp. n., P. glabra sp. n., and P. singaporensis sp. n. A key to the species of the new genus is provided.