Background Reversible cerebral vasoconstriction syndrome (RCVS) is a common cause of thunderclap headache (TCH), mainly recurrent, sometimes associated with seizures and/or neurological deficit. Association with amnesia is exceptional. We report a case series of RCVS concomitant with transient global amnesia (TGA) and propose pathophysiologic hypotheses. Methods We retrospectively reviewed clinical and radiological features of patients diagnosed with confirmed concomitant RCVS and TGA between 2012 and 2018 in two specialized institutions. Results Two women aged 67 and 53, and a 64-year-old man had a first thunderclap headache triggered by an acute emotional stress, rapidly followed by TGA. Amnesia resolved within a few hours and RCVS was proven for all, with complete resolution of vasospasms within 3 months. All three patients had excellent outcome. Conclusions RCVS and TGA can occur simultaneously, which suggests common mechanisms such as aberrant responses to physical or emotional stress and cerebral vasoconstriction.