Capo dei capi or capo di tutti i capi or Godfather are terms used mainly by the media, public, fiction writers and law enforcement community to indicate a supremely powerful crime boss in the Sicilian or American Mafia who holds great influence over the whole organization. The term was introduced to the U.S. public by the Kefauver Commission in 1950.

The Sicilian Mafia or Cosa Nostra, also referred to as simply Mafia, is a criminal society originating on the island of Sicily and dates back to the mid-19th century. It is an association of gangs which sell their protection and arbitration services under a common brand. The Mafia's core activities are protection racketeering, the arbitration of disputes between criminals, and the organizing and oversight of illegal agreements and transactions.