Niccolò Paccanari (1773 – c. 1811) was an Italian Catholic priest and the founder of the Society of the Faith of Jesus.

Paccanari was born in 1773 in Borgo Valsugana, Trentino.^[1] In his youth, he had little formal education; he became a soldier and was engaged in business.

In 1795, he became gravely ill and spent 14 months in prayer and recuperation with a confraternity at the Oratory of San Francesco Saverio del Caravita in Rome.^[2] At the end of this period, Paccanari established a religious congregation called the Society of the Faith of Jesus on 15 August 1797,^[2] whose purpose was to continue as the successor of the Society of Jesus, which had been suppressed by the pope.^[3] His four confrères elected him as the first superior of the new congregation.^[2] In 1798, Paccanari founded a novitiate for the congregation in Spoleto, Umbria.^[1]

Paccanari was jailed three times in Castel Sant'Angelo during the short-lived Roman Republic. In 1800, he was ordained a priest.^[1] As the congregation grew to more than 100 individuals across Europe, the members became dissatisfied with Paccanari, who they accused of being ambitious and materialistic.^[2]

As internal strife grew, Paccanari was investigated by the Roman Inquisition,^[1] which found him guilty and sentenced him to 10 years in prison in August 1808.^[2] However, Paccanari was released from prison in 1809 by the French occupiers of Rome. The following year, he again spent time in prison for another offense.^[2]

It is not certain when or how Paccanari died. In 1811, a decapitated body was found in the Tiber River in Rome, which was identified as his.^[4][1]