Onano is a comune (municipality) in the Province of Viterbo in the Italian region Lazio, located about northwest of Rome and about northwest of Viterbo.
Onano borders the following municipalities: Acquapendente, Gradoli, Grotte di Castro, Latera, Sorano. Alongside Ala, Ateleta, Orero and Siris. It is one of five Italian municipalities with a palindromic name.