More than 1,000 species of bambusicolous fungi have been reported worldwide, although most lack modern morphological description and phylogenetic investigation. Two species of bambusicolous fungi were collected in northern Thailand. Based on morphological characters, and on a comparison with type specimens, they were determined to be Pteridiospora javanica and Roussoellopsis macrospora. In a multigene phylogenetic analysis Pteridiospora javanica formed a sister clade with Astrosphaeriella stellata, while Roussoellopsis macrospora clustered with R. tosaensis in Roussoellaceae. Because the current placement of Astrosphaeriella in Dothideomycetes cannot presently be resolved, the family placement of Pteridiospora javanica is also unresolved. Based on morphology and phylogeny we epitypify our strains under the names Pteridiospora javanica and Roussoellopsis macrospora. Asexual states are also described for both species.