Protomicrocotylidae is a family of monogenean parasites in the order Mazocraeidea. The type-genus of the family is Protomicrocotyle. The genus was created in 1922 by Thomas Harvey Johnston and Oscar Werner Tiegs for a worm previously described under the name Acanthodiscus mirabile by MacCallum in 1918. The worm was parasitic on a crevalle jack of the New York Aquarium. Johnston & Tiegs originally proposed to create the subfamily Protomicrocotylinae, which was later raised to family level.