The genus Platyscelio Kieffer (Hymenoptera: Platygastridae, Scelioninae) is a widespread group in the Old World, found from West Africa to northern Queensland, Australia. The species concepts are revised and a key to world species is presented. The genus is comprised of 6 species, including 2 known species which are redescribed: Platyscelioafricanus Risbec (Benin, Cameroon, Central African Republic, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Kenya, Mozambique, Nigeria, Sierra Leone, South Africa, Tanzania, Togo, Uganda, Yemen, Zimbabwe); and Platysceliopulchricornis Kieffer (Australia, Bangladesh, China, India, Indonesia, Japan, Malaysia, Papua New Guinea, Philippines, Solomon Islands, Taiwan, Thailand, Vanuatu, Vietnam). Five species-group names are considered to be junior synonyms of Platysceliopulchricornis: Platyscelioabnormis Crawford syn. n., Platysceliodunensis Mukerjee syn. n., Platysceliomirabilis Dodd syn. n., Platysceliopunctatus Kieffer syn. n., and Platysceliowilcoxi Fullaway. The following species are hypothesized and described as new taxa: Platyscelioarcuatus Taekul & Johnson, sp. n. (Western Australia); Platysceliomysterium Taekul & Johnson, sp. n. (Zimbabwe, Botswana, South Africa); Platysceliomzantsi Taekul & Johnson, sp. n. (South Africa); and Platysceliostriga Taekul & Johnson, sp. n. (Western Australia).