Diffuse intrinsic pontine gliomas (DIPG) are an aggressive type of pediatric brain tumor with a very high mortality rate. Surgery has a limited role given the tumors location. Palliative radiation therapy alleviates symptoms and prolongs survival, but median survival remains less than 1 year. There is no clear role for chemotherapy in DIPGs as trials adding chemotherapy to palliative radiation therapy have failed to improve survival compared to radiation alone. Thus, there is a critical need to identify tissue-specific radiosensitizers to improve clinical outcomes for patients with DIPGs. Pharmacologic (high dose) ascorbate (P-AscH^–) is a promising anticancer therapy that sensitizes human tumors, including adult high-grade gliomas, to radiation by acting selectively as a generator of hydrogen peroxide (H₂O₂) in cancer cells. In this study we demonstrate that in contrast to adult glioma models, P-AscH– does not radiosensitize DIPG. DIPG cells were sensitive to bolus of H₂O₂ but have faster H₂O₂ removal rates than GBM models which are radiosensitized by P-AscH^–. These data support the hypothesis that P-AscH– does not enhance DIPG radiosensitivity, likely due to a robust capacity to detoxify and remove hydro-peroxides.