The genetic diversity of Tamarixia radiata Waterston (Hymenoptera: Eulophidae) laboratory colonies derived from collections in China, northern Vietnam, Pakistan, and a mixed colony from Taiwan and southern Vietnam was evaluated using the internal transcribed spacer (ITS) region 1, ITS-2, and the 5′ end of the cytochrome oxidase subunit I gene. The strains share the same ITS sequence, consistent with the morphological hypothesis that the collections represent a single species. The COI marker was variable and could distinguish the northern Vietnam and Pakistan colonies from each other and from the other colonies. Comparison of COI sequences from field-collected populations of Puerto Rico, Guadeloupe, and Texas indicates that Florida is not a likely source of the introduction into Puerto Rico but is a likely source of the introduction into Texas.