Vincent Ferrer, OP (Valencian: Sant Vicent Ferrer [ˈsaɱ viˈsɛɱ feˈreɾ]; Spanish: San Vicente Ferrer; Italian: San Vincenzo Ferreri; German: Sankt Vinzenz Ferrer; Dutch: Sint-Vincent Ferrer; French: Saint Vincent Ferrier; 23 January 1350 – 5 April 1419) was a Valencian Dominican friar who gained acclaim as a preacher, missionary and logician. After supporting Antipope Benedict XIII during the Western Schism, Ferrer travelled to preach across Western Europe and the British Isles. His preaching has been credited in some sources as converting 25,000 Jews to Catholicism, other sources indicate that they involved supporting coercive means, such as the forcible conversion of synagogues into churches. He was canonized in 1455.

Vincent was the fourth child of Guillem Ferrer, a notary from Palamós, and his wife, Constança Miquel, apparently from Valencia itself or Girona.

Legends surround Vincent's birth. It was said that his father was told in a dream by a Dominican friar that his son would be famous throughout the world. His mother is said never to have experienced pain when she gave birth to him. He was named after Vincent Martyr, the patron saint of Valencia. He would fast on Wednesdays and Fridays and distribute alms to the poor. He began his classical studies at the age of eight, and his study of theology and philosophy at fourteen. Four years later, at the age of eighteen, Ferrer entered the Order of Preachers, commonly called the Dominican Order (in England also known as "Black Friars" because of the black cloak they wear over their white habits). As soon as he had entered the novitiate of the Order, though, he experienced temptations urging him to leave. Even his parents pleaded with him to do so and become a secular priest. He prayed and practiced penance to overcome these trials. Thus he succeeded in completing the year of probation and advancing to his profession.

For a period of three years, he read solely Sacred Scripture and eventually committed it to memory. He published a treatise on Dialectic Suppositions after his solemn profession, and in 1379 was ordained a Catholic priest at Barcelona. He eventually became a Master of Sacred Theology and was commissioned by the Order to deliver lectures on philosophy. He was then sent to Barcelona and eventually to the University of Lleida, where he earned his doctorate in theology.

Vincent Ferrer is described as a man of medium height, with a lofty forehead and very distinct features. His hair was fair in colour and tonsured. His eyes were very dark and expressive; his manner gentle. Pale was his ordinary colour. His voice was strong and powerful, at times gentle, resonant, and vibrant.

The Western Schism (1378–1417) divided Catholicism between two, then eventually three, claimants to the papacy. Antipope Clement VII lived at Avignon in France, and Pope Urban VI in Rome. Vincent was convinced that the election of Urban was invalid, although Catherine of Siena was just as devoted a supporter of the Roman pope. In the service of Cardinal Pedro de Luna, Vincent worked to persuade Spaniards to follow Clement. When Clement died in 1394, Cardinal de Luna was elected as the second antipope successor to the Avignon papacy and took the name Benedict XIII.

Vincent and his brother Boniface, General of the Carthusians, were loyal to Benedict XIII, commonly known as "Papa Luna" in Castile and Aragon. He worked for Benedict XIII as apostolic penitentiary and Master of the Sacred Palace. Nonetheless Vincent labored to have Benedict XIII end the schism. When Benedict XIII did not resign as intended at either the Council of Pisa (1409) or the Council of Constance (1414–1418), he lost the support of the French king and of most of his cardinals, and was excommunicated as a schismatic in 1417.

Vincent later claimed that the Western Schism had had such a depressing effect on his mind that it caused him to be seriously ill.