Parmastomyces is a genus of fungi in the family Fomitopsidaceae. The genus was circumscribed by Czech mycologists František Kotlaba and Zdenek Pouzar in 1964, with Tyromyces kravtzevianus Bondartzev & Parm. as the type species. Parmastomyces species cause a brown rot. The genus has a monomitic hyphal system.