Helobdella octatestisaca Lai and Chang, 2009, was originally described from Taiwan where it is believed to have been introduced. It has subsequently been reported from throughout much of Mexico. Helobdella octatestisaca was collected from a small pond in Walker County, Texas, U.S.A., representing the first report of this species from the United States. Helobdella octatestisaca occurred primarily associated with red-eared slider turtles, Trachemys scripta, and common mud turtles, Kinosternon subrubrum. Individuals of H. octatestisaca were frequently found within clusters of juveniles of the common turtle leech, Placobdella parasitica, and were often attached to individuals of P. parasitica. It was hypothesized that H. octatestisaca is utilizing P. parasitica as a source of food and that Helobdella spp. preferentially associate with turtles, thereby gaining enhanced access to prey items.