Matteo Orsini de Campo Flore (died probably on 18 August 1340) was an Italian Dominican and Cardinal.
He was the nephew of Cardinal Francesco Napoleone Orsini (1295-1312), who was himself the nephew of Pope Nicholas III (Giovanni Gaetano Orsini).
His early studies were at Bologna, where he studied law and took the Bacculaureate.
He was Canon of the Church of S. Etienne in Châlons sur Saône. He entered the Dominican Order at the Convent of S. Jacques in Paris, around 1294, and completed the full course of theology. He returned to Italy, but the Provincial of the Roman Province sent him back to Paris in 1306, where he obtained the Degree of Master. He taught biblical studies at Paris, Florence, and Rome. In 1311 he attended the Capitulum Generale in Naples as socius ('companion') of the Definitor (elected delegate) of the Roman Province, the Provincial Fr. Lapus Cerli. In 1314, the Capitulum Generale at London appointed him Vicar for the itinerant preachers of the Order.
After teaching in Paris in 1316 Fr. Matteo Orsini, OP, is held to have taught at the Dominican stadium generale at the Convent of Santa Maria sopra Minerva. This would have meant that he was an in-house teacher in a Dominican convent studium: instructors in Philosophy were called Lector, instructors in Theology were called Magister; he was not a University Regent Master.
He was Prior of the Convent of the Minerva. He won distinction by his zeal for the spread of the order, and was elected Provincial of the Roman Province in 1322 in the provincial Chapter at Orvieto. In 1323, during a meeting of the Chapter of the Roman Province at Città di Castello (Tiferno), he and the Definitores were attacked by a deranged novice, Fr. Jacobus Dombellinghi, who injured Fr. Matteo with his sword. He attended the General Chapter of the Order at Bordeaux in June, 1324. On his return from the General Chapter he fell into a serious illness which almost cost him his life. In 1326, Fr. Matteo was relieved of his duty as Provincial of the Roman Province and succeeded by Fr. Bertramus Monaldeschi, who was elected by the General Chapter meeting in Paris. Fr. Matteo was appointed Vicar for the Master General in Italy.
Orsini's service as Vicar of the Master General was short-lived. On 20 October 1326, the pope named Matteo Orsini, OP, Bishop of Girgenti (Agrigento), in Sicily, and then, six months later (15 June 1327), transferred him to the archiepiscopal see of Siponto, (Manfredonia, Southern Italy). He arrived in Siponto on 22 April 1327, according to Pompeo Sarnelli, which is completely impossible chronologically, since Fr. Matteo was not appointed until 15 June 1327. And in any case he was named a cardinal in December 1327, and on 11 January 1328 a successor to him at Siponto was appointed by John XXII.