The omertà (Sicilian for "manliness") is the vow of silence taken by members of the Italian Mafia.

Particularly, it means that mafiosos will not involve the police or the government in the affairs of the mafia. Joe Valachi was the first person to betray the omertà when he publicly spoke out about the existence of the mafia, when he testified before the United States Congress.

Omertà (or, in some markets, Omerta) was the title of the last novel written by Mario Puzo.