A taxonomic revision of the South African mealybug genus Octococcus Hall is presented. Most species of this genus feed on plants in the Asteraceae. Six species are treated, namely, O. barbarae, O. gullanae. and O. warniae which are described as new. The three previously described species are: Octococcus africanus (Brain), O. minor De Lotto, and O. pentziae Hall. Octococcus salsolicola (Priensner & Hosny), which was described originally as Ripersia salsolicola, is treated as a nomen dubium. Adult females of all species are described and illustrated and a key for their identification is presented. Illustrations and descriptions are also presented of first-instar nymphs of Octococcus africanus, O. minor, and O. warniae and a key for their identification is presented. Descriptions and illustrations are also given for a second-instar nymph of O. africanus and a third-instar nymph of O. warniae.