Henicovalva gen. n. (Lepidoptera: Geometridae: Ennominae), a new genus of ennomine geometrids characterised by unusually complex male and female genitalia, is described and illustrated. In addition to the East African type species H. xera (Prout, L. B., 1922) comb. n., which is transferred from Odontopera Stephens, 1831, nine additional members of this genus are described as new to science: H. serulensis sp. n. from northeastern Botswana, H. mpisiensis sp. n. from Swaziland, H. lebomboensis sp. n. from northern KwaZulu-Natal, H. dissoluta sp. n. from northeastern Tanzania, H. staudei sp. n. from central Kenya, H. praedicta sp. n. from southwestern Kenya, H. pulveraria sp. n. from Rwanda, H. negus sp. n. from Ethiopia, and H. yemenensis sp. n. from the Yemen Arab Republic. Although the recorded distribution of Henicovalva gen. n. is disjunct, this may be due to sampling bias. The phylogenetic position of the new genus within Ennominae is discussed, and it is tentatively placed in Ennomini. Illustrations of the adults and male and female genitalia, where known, are provided, as is a map showing the distribution of the southern African species. The study is complemented by a Gazetteer.