Three species of Peroneutypa were collected from dead wood in Thailand. Two new taxa P. diminutiasca and P. rubiformis are herein described, illustrated and compared with related taxa, based on the evidence from morphology and phylogenetic analyses. Details for the holomorphs of P. rubiformis and the third species P. scoparia are provided. Phylogenetic analyses of a combined ITS and TUB2 DNA sequence dataset support their placement in the genus Peroneutypa (Diatrypaceae, Xylariales). An updated key to Peroneutypa species is also provided.