Three species of Ooctonus (Hymenoptera: Mymaridae) are described from South Africa: O. albiclavus Huber, sp. n., O. capensis Huber, sp. n., and O. infuscatus Huber, sp. n. They represent the first records of Ooctonus from the Afrotropical Region and the first described species of Ooctonus native to the southern hemisphere. The only previously named Ooctonus from Africa (Madagascar), O. sevae Risbec, was transferred recently to Gonatocerus. A lectotype and paralectotypes are designated here for the slide-mounted and two card-mounted syntypes, respectively, of this species. One species in New Zealand, Ooctonus vulgatus Haliday, is an accidental introduction from the northern hemisphere. Online interactive keys to the South African species are available at:  http://www.waspweb.org/Chalcidoidea/Mymaridae/Keys/index.htm