Pentito (Italian pronunciation: [penˈtiːto]; lit. "repentant"; plural: pentiti) is used colloquially to designate collaborators of justice in Italian criminal procedure terminology who were formerly part of criminal organizations and decided to collaborate with a public prosecutor. The judicial category of pentiti was originally created in 1970s to combat violence and terrorism during the period of left-wing and right-wing terrorism known as the Years of Lead. During the 1986–87 Maxi Trial and after the testimony of Tommaso Buscetta, the term was increasingly applied to former members of organized crime in Italy who had abandoned their organization and started helping investigators.

In exchange for the information they deliver, pentiti receive shorter sentences for their crimes, in some cases even freedom. In the Italian judicial system, pentiti can obtain personal protection, a new name, and some money to start a new life in another place, possibly abroad.

This practice is common in other countries as well. In the United States, criminals testifying against their former associates can enter the Witness Protection Program, and be given new identities with supporting paperwork. The Italian Mafia bosses Buscetta and Francesco Marino Mannoia were allowed to live in the U.S. under new identities in the Witness Protection Program when Italy did not yet have such a program.

Among the most famous Mafia pentiti is Tommaso Buscetta, the first important pentito. He was helpful to judge Giovanni Falcone in describing the Sicilian Mafia Commission or Cupola, the leadership of the Sicilian Mafia in the 1980s, and identifying the main operational channels that the Mafia used for its business.

In Italy, important successes were achieved with the cooperation of pentiti in the fight against terrorism (especially against the Red Brigades), by Carabinieri general Carlo Alberto Dalla Chiesa (who was later killed by the Mafia).

In the period until the 1990s, there were few, albeit significant, pentiti such as Tommaso Buscetta, Salvatore Contorno, Antonino Calderone, etc. However, this changed during the early 1990s. From 1992, over a thousand mafiosi have agreed to collaborate with Italian justice.

In some cases, pentiti have invented stories to obtain reductions in jail time. A famous case regarded the popular TV anchorman Enzo Tortora, who was falsely accused of cocaine trafficking and Camorra membership by a pentito named Giovanni Melluso. Tortora was detained for years before being cleared; he developed cancer and died soon after the case was finally solved, some say because of the emotional stress of his imprisonment.

In some southern Italian communities, the Mafia has a significant presence, and in these areas becoming a pentito is tantamount to a death sentence. Indeed, the Mafia family of Totò Riina based in the town of Corleone habitually extended the death sentence of the pentiti over to their relatives. For example, several of Tommaso Buscetta's close family members were killed in a long series of murders.