In Etruscan mythology, Voltumna or Veltha was the chthonic (relating to or inhabiting the underworld) deity, who became the supreme god of the Etruscan pantheon, the deus Etruriae princeps, according to Varro. Voltumna's cult was centered in Volsini (modern-day Orvieto) a polis of the Etruscan Civilization of central Italy.
The bond of the twelve Etruscan populi was renewed annually at the sacred grove of Fanum Voltumnae, the sanctuary of Voltumnus sited near Volsinii (present day Bolsena), which was mentioned by Livy. At the Fanum Voltumnae ludi were held, the precise nature of which, whether athletic or artistic, is unknown.
In the Roman Forum, near the Temple of Castor and Pollux stood a shrine dedicated to Voltumna in the Vicus Tuscus.
He was the equivalent of the Roman Vertumnus.