The Microascales are an order of fungi in the class Sordariomycetes, subclass Hypocreomycetidae. This is a relatively small order of mostly saprobic fungi that live in soil, rotting vegetation and dung. Some species are plant pathogens, such as Ceratocystis fimbriata, transmitted by beetles to living trees and causing cacao wilt and many other economically important diseases. Species in the genus Pseudallescheria (family Microascaceae) are pathogenic to humans, for example, Pseudallescheria boydii can cause allergic bronchopulmonary disease. The order was circumscribed in 1980.