Cervical artery dissection (CAD) is an important etiology of stroke in young adults. Its etiology is incompletely understood. Here, we report a young woman who presented with acute ischemic stroke in the setting of internal carotid artery (ICA) dissection and essential thrombocythemia (ET). We present a review of previous cases with comorbidity of CAD and ET and discuss the pathophysiological implications of this co-occurrence. In particular, we speculate that ET may increase the susceptibility of cervical vessels to spontaneous dissection, for example, by disturbing the microcirculation within the vessel wall.