Fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidóptera: Noctuidae), is the most important insect pest of maize, Zea mays L., because it causes great economic loss and insecticide to be overused for its control, which increase costs of production and contaminate the environment. However, the pest is naturally controlled by various parasitoids of the Tachinidae family. Here, we report molecular identification of a new species of the genus Lespesia parasitizing larvae of S. frugiperda in the central region of Chiapas, México.