The Diadocidiidae are a family of flies (Diptera).Two genera with over 20 species are described. Diadocidiidae are found worldwide, except in Africa and Antarctica. They are usually considered close to the Keroplatidae, Bolitophilidae, and Ditomyiidae, and used to be included in the Mycetophilidae. They are woodland flies. The larvae spin silken tubes under bark or in dead logs.