Haemogregarines are blood parasites with a life-cycle involving a vertebrate as the intermediate host and an invertebrate as the definitive host and vector. Extensive phylogenetic investigations based on 18S-rRNA gene sequences have shown thatHaemogregarina stepanowi(Apicomplexa: Haemogregarinidae) is able to infest a large diversity of freshwater turtle species, including the European pond turtleEmys orbicularis, the Sicilian pond turtleEmys trinacris, the Caspian turtleMauremys caspica, the Mediterranean pond turtleMauremys leprosa, and the Western Caspian turtleMauremys rivulata, among others. From the same molecular markers,H. stepanowiis further considered to be a complex of cryptic species predisposed to infect the same host species. WhilePlacobdella costatais known to be the unique vector ofH. stepanowi, it is only recently that independent lineages withinP. costatahave been illustrated—suggesting the presence of at least five unique leech species across Western Europe. The aims of our study were therefore to investigate from mitochondrial markers (COI) the genetic diversity within haemogregarines and leeches infecting freshwater turtles of the Maghreb, in order to identify processes of parasite speciation. We showed thatH. stepanowiconsists of at least five cryptic species in the Maghreb, while twoPlacobellaspecies were identified in the same area. Although an Eastern–Western speciation pattern was apparent for both leeches and haemogregarines, we cannot make definitive conclusions regarding co-speciation patterns between parasites and vectors. However, we cannot reject the hypothesis of a very strict host–parasite specificity within leeches.