Plasmodium ovale is a species of parasitic protozoa that causes tertian malaria in humans. It is one of several species of Plasmodium parasites that infect humans including Plasmodium falciparum and Plasmodium vivax which are responsible for most malarial infection. It is rare compared to these two parasites, and substantially less dangerous than P. falciparum.
P. ovale is primarily concentrated in sub-Saharan Africa and islands in the western Pacific. However P. ovale has also been reported in the Philippines, eastern Indonesia, and Papua New Guinea, as well as Bangladesh, Cambodia, India, Thailand and Vietnam.