Vertigo /ˈvɜrtɨɡoʊ/ (from the Latin vertō "a whirling or spinning movement") is a subtype of dizziness in which a patient inappropriately experiences the perception of motion (usually a spinning motion) due to dysfunction of the vestibular system. It is often associated with nausea and vomiting as well as a balance disorder, causing difficulties standing or walking. There are three types of vertigo. The first is known as objective and describes when the patient has the sensation that objects in the environment are moving; the second is known as subjective and refers to when the patient feels as if he or she is moving, and the third is known as pseudovertigo, an intensive sensation of rotation inside the patient's head. While appearing in textbooks, this classification has little to do with the pathophysiology or treatment of vertigo.

Dizziness and vertigo are common medical issues, affecting approximately 20%-30% of the general population. Vertigo may be present in patients of all ages. The prevalence of vertigo rises with age and is about two to three times higher in women than in men. It accounts for about 2-3% of emergency department visits. The main causes of vertigo are benign paroxysmal positional vertigo, Ménière's disease, vestibular neuritis, and labyrinthitis, but may also be caused by a concussion or a vestibular migraine. Excessive consumption of ethanol (alcoholic beverages) can also cause symptoms of vertigo. Repetitive spinning, as in familiar childhood games, can induce short-lived vertigo by disrupting the inertia of the fluid in the vestibular system; this is known as physiologic vertigo.