Updated publication reference for PubMed record(s): 32894330. Multiple sclerosis (MS) is the most frequent demyelinating disease and despite significant advances in the immunotherapy, disease progression still cannot be prevented. Promotion of remyelination, an endogenous repair process, represents a promising new treatment approach. However, spontaneous remyelination frequently fails in MS lesions due to an impaired differentiation of progenitor cells into mature, myelinating oligodendrocytes. Intrinsic oligodendroglial and extrinsic inflammatory factors may contribute to this differentiation block. Therefore, we compared induced pluripotent stem cell (iPSC)-derived oligodendrocytes (hiOL) from MS patients and healthy controls as well as their response to extrinsic factors. While functional capabilities or proteome compostion of both cell types were virtually indistinguishable, we discovered that Interferon-gamma (IFNγ) producing immune cells significantly impaired oligodendroglial differentiation and observed no differences in the functional capabilities or the proteome. In summary, these data indicate that the oligodendroglial differentiation block is not due to intrinsic oligodendroglial factors, but rather caused by the inflammatory environment present in MS lesions. These findings may contribute to the development of remyelination promoting strategies in MS.