Napoleone Orsini (1263 – 24 March 1342) was a Roman Cardinal. His ecclesiastical career lasted 57 years, 54 of them as a cardinal, and included six conclaves. Born in Rome to Rinaldo Orsini, Lord of Monterotondo and of Marino, son of Matteo Rosso Orsini 'il Grande'; and Ocilenda, perhaps the daughter of Stefano II Conti, perhaps of a member of the house of Boveschi. Rinaldo was a brother of Pope Nicholas III and of Cardinal Giordano Orsini. Napoleone took holy orders in 1285 and was named a papal sub-chaplain by Honorius IV. He is attested as Papal Chaplain on February 18, 1286. He rose quickly in the ecclesiastical hierarchy, and in a Consistory held by Pope Nicholas IV on 16 May 1288, he was appointed a Cardinal Deacon and assigned the Deaconry of S. Adriano.