A new species of rhynchobdellid leech, Placobdella ringueleti n. sp., is described based on the examination of 25 specimens. Leeches were collected from body appendages of freshwater turtles (Kinosternon leucostomum, Dermatemys mawii, and Staurotypus triporcatus) from Chiapas, Mexico. The new species resembles other members of the genus in the ocular morphology, bilobated ovaries, and presence of 1 pair of elongated mycetomes, but it is distinguished from them by the dorsal papillar pattern, by having a continuous longitudinal mid-dorsal stripe along the dorsal surface and papillae on the dorsal surface of the posterior sucker. Placobdella ringueleti represents the third species of the genus in Mexico. The type locality of the new species is part of the “El Ocote” Biosphere Reserve, Chiapas, Mexico.