Paroxysmal sympathetic hyperactivity (PSH) is a complication of severe traumatic or hypoxic brain injury characterized by transient episodes of tachycardia, tachypnea, hypertension, hyperthermia, diaphoresis, and/or dystonic posturing. Posttraumatic "sympathetic storms" are associated with poor outcomes. PSH rarely occurs after brain tumor resection in pediatric patients; only 4 cases have been published since 1929. Thus, the authors sought to report their experience with postcraniotomy PSH in pediatric brain tumor patients. A retrospective study of patients younger than 18 years of age who underwent craniotomy for brain tumor resection at a single center by a single surgeon over a 7-year period was performed. A clinical diagnosis of postoperative PSH was recorded. Recorded outcomes included the interval between surgery and initiation of cytotoxic therapy, need for long-term CSF diversion, length of hospital stay, and survival. Of the 150 patients who were included for analysis, 4 patients were diagnosed with postoperative PSH for an overall occurrence of 2.7%. PSH patients were younger than non-PSH patients (1.8 ± 0.4 years vs 9.2 ± 5.3 years, p = 0.010) and tended to have intraventricular tumors close to the thalamus, basal ganglia, and/or brainstem. PSH patients experienced longer hospital admissions (44.3 ± 23.4 days vs 6.8 ± 9.4 days, p = 0.001), a shorter interval between surgery and initiation of cytotoxic cancer-directed therapy (14.3 ± 8.0 days vs 90.7 days ± 232.9 days, p = 0.011), and increased need for long-term CSF diversion compared with non-PSH patients (75% vs 25%, p = 0.005). At the last follow-up, 50% of PSH patients had died compared with 13% of non-PSH patients (p = 0.094). PSH is a rare postoperative complication that may affect young children with periventricular tumors and is associated with poorer clinical outcomes. Increasing awareness of this condition is vital to improving patient outcomes.