Mesostigmata is an order of mites belonging to the Parasitiformes. They are by far the largest group of Parasitiformes, with over 8,000 species in 130 families. Mesostigmata includes parasitic as well as free-living and predatory forms. They can be recognized by the single pair of spiracles positioned laterally on the body.
The family with the most described species is Phytoseiidae. Other families of note are Diplogyniidae, Macrochelidae, Pachylaelapidae, Uropodidae and Veigaiidae.