The Gadianton robbers (/ɡæd.iː.ˈæn.tʌn/), according to the Book of Mormon, were a secret criminal organization in ancient America.
The society was founded around 52 BC or 51 BC by Nephite supporters of Paanchi, an unsuccessful candidate for the position of chief judge. Paanchi had been executed for treason when he refused to accept the election of his brother Pahoran II to the judgment seat and tried to incite a revolution, and one of his supporters, Kishkumen (/kɪʃ.ˈkuː.mən/), assassinated Pahoran in retaliation. Kishkumen and his associates entered into a pact to keep the assassin's identity a secret.
A man named Gadianton became the leader of Kishkumen's secret group. He arranged for Kishkumen to assassinate Chief Judge Helaman II, promising that if he, Gadianton, were made chief judge he would appoint the other members of the band to positions of authority. Kishkumen was apprehended and killed by one of Helaman's servants, and Gadianton and his followers, fearing the same fate, fled into the wilderness.