Rosa-associated fungi are rich in species and diverse in function, with many potential new taxa. However, only a few publications have reported Rosa-associated endophytic fungi using a combination of molecular systematics and morphology. Rosa roxburghii is an economically important source of medicine and food. We reported earlier the diversity and antimicrobial activities of the fungal endophytes of this plant, but further confirmation is needed for possible new taxa. In this study, we describe 10 novel species and two new host records isolated from healthy tissues of R. roxburghii while identifying three new combinations, all belonging to the Sordariomycetes. The new species described herein include Chaetomium rosifloricola, Chaetomium rosiradicicola, Chrysofolia fructicola, Coniella cili, Hypoxylon florendophyticum, Hypoxylon rosicaulendophyticum, Ilyonectria radicigena, Neopestalotiopsis caulicola, Neopestalotiopsis fructicola, and Seimatosporium endophyticum. Monochaetia bulbophylli, Neopestalotiopsis anacardii, and Neopestalotiopsis termitarii were introduced as new combinations, while Coniella quercicola and Hypoxylon pulicicidum were described as new host records on R. roxburghii. All the taxa have been described, illustrated, and phylogenetically analyzed, in addition to the lifestyles of each genus. Altogether, the results of this study have important implications for identifying novel endophytic fungi and developing potential applications of these fungi in the future.