In dentistry, hyperdontia is the condition of having supernumerary teeth, teeth which appear in addition to the regular number of teeth. The occurrence of hyperdontia ranges from 0.1% to 3.8% in various populations. There is evidence of hereditary factors along with some evidence of environmental factors leading to this condition. Many supernumerary teeth never erupt, but they may delay eruption of nearby teeth or cause other dental problems. Molar-type extra teeth are the rarest form. Dental X-rays are often used to diagnose hyperdontia.

A similar condition is hypodontia, in which there are fewer than the usual number of teeth.