Thyrea is a genus of lichen-forming fungi in the family Porocyphaceae. It contains four species that have been accepted by Species Fungorum.
The genus was circumscribed by Italian lichenologist Abramo Bartolommeo Massalongo in 1856, with Thyrea plectospora assigned as the type species. In a multilocus phylogeny and molecular phylogenetics-informed reclassification of the Lichinomycetes published in 2024, MarÃÂa Prieto, Mats Wedin and Matthias Schultz placed Thyrea in the emended family Porocyphaceae.