Introduction Nelarabine is now increasingly being used for the treatment of relapsed T-cell acute lymphoblastic leukemia/lymphoma, and about 18% of patients experience ≥ grade 3 toxicity. Despite the increasing use of this drug, there are no guidelines for managing its neurotoxicity. We would like to share our experience with one such case. Case Report A sixteen-year-old girl with T-lymphoblastic lymphoma received Nelarabine as part of her relapse treatment. Three weeks post-treatment, patient presented with worsening encephalopathy, bulbar palsy, and seizures. Management and outcome After a detailed evaluation, Nelarabine neurotoxicity was strongly considered and was managed with a combination of steroids, intravenous immunoglobulin, and aminophylline, with almost complete recovery starting at 72 hours of treatment initiation. Discussion Despite the increasing use of this drug, guidelines for the management of the neurological adverse effects of Nelarabine are lacking. The above-mentioned combination of drugs worked for our patient, but larger numbers are needed to validate this as an approved treatment regimen.