Glioblastoma (GBM) is one of the most aggressive primary malignant brain tumors. The major challenge is the lack of effective therapeutic drugs due to the blood–brain barrier (BBB) and tumor heterogeneity. Remdesivir (RDV), a new member of the nucleotide analog family, has previously been shown to have excellent antiviral effects and BBB penetration, and was predicted here to have anti-GBM effects. In vitro experiments, RDV significantly inhibited the growth of GBM cells, with IC₅₀ values markedly lower than those of normal cell lines or the same cell lines treated with temozolomide. Moreover, in multiple mouse models, RDV not only distinctly inhibited the progression and improved the prognosis of GBM but also exhibited a promising biosafety profile, as manifested by the lack of significant body weight loss, liver or kidney dysfunction or organ structural damage after administration. Furthermore, we investigated the anti-GBM mechanism by RNA-seq and identified that RDV might induce apoptosis of GBM cells by enhancing endoplasmic reticulum (ER) stress and activating the PERK-mediated unfolded protein response. In conclusion, our results indicated that RDV might serve as a novel agent for GBM treatment by increasing ER stress and inducing apoptosis in GBM cells.