Hypomyces species are recognized for their fungicolous lifestyle. These species are globally distributed across various habitats from temperate to tropical and subtropical regions. This study introduces a novel fungicolous Hypomyces species, Hypomyces chiangraiensis associated with Mycena sp. in northern Thailand. Three new combinations within the genus, Hypomyces novovarius, Hypomyces paravirescens and Hypomyces protrusus are proposed. Additionally, new geographical records for Hypomycescornea, Hypomycesnovovarius and Hypomyces semicircularis are documented. A new host record for Hypomycescornea is documented. All species identifications relied on morphological features coupled with phylogenetic analyses of the combined internal transcribed spacer region (ITS1-5.8S-ITS2), partial 28S large subunit (nc LSU rDNA), partial translation elongation factor (TEF1α), and partial second largest subunit of the DNA-directed RNA polymerase II (RPB2) sequence matrix. Comprehensive descriptions, illustrations, and a phylogenetic tree to show the placements of taxa are provided. The morphological characters of the novel species are compared with sister taxa.