Headaches are one of the most common neurologic complaints leading to emergency room visits in pediatric patients. Of the different type of headache presentations, thunderclap headaches require a particularly urgent work-up. In children, recurrent thunderclap headaches are more often associated with reversible cerebral vasoconstriction syndrome (RCVS) than other etiologies such as subarachnoid hemorrhage. RCVS is a vascular disorder of incompletely understood etiology, characterized by diffuse vasoconstriction of the cerebral arterial vasculature, and commonly associated with recurrent severe headaches. Patients may experience focal neurological deficits, due to hemorrhages, infarcts, and even posterior reversible encephalopathy syndrome . Although RCVS has been best characterized in adults, it does occur in children. This review summarizes the presentation of RCVS in children and highlights some of the differences with the adult population.