Smicromorpha Girault (Hymenoptera: Chalcididae) is distributed in the old world tropics and subtropics from Australia through New Guinea, Southeast and South Asia. Since its original description in 1913 conclusive evidence of its host has been lacking although it has been collected in association with weaver ants (Oecophylla spp.; Formicidae: Formicinae) either in proximity to ant nests or, on one occasion, reared from one. In this paper we report the presence of Smicromorpha pupae within the gaster of Oecophylla longinoda workers from a nest collected in coastal Kenya. This discovery extends the distribution of Smicromorpha to the Afrotropical Region and demonstrates conclusively that they are koinobiont parasitoids of weaver ants.