The 1378 papal conclave which was held from April 7 to 9, 1378, was the papal conclave which was the immediate cause of the Western Schism in the Catholic Church. The conclave was one of the shortest in the history of the Catholic Church. The conclave was also the first since 1159 held in the Vatican and in Old St. Peter's Basilica.

Pope Urban VI, born Bartolomeo Prignano, was head of the Catholic Church from 8 April 1378 to his death, in October 1389. He was the most recent pope to be elected from outside the College of Cardinals. His pontificate began shortly after the end of the Avignon Papacy. It was marked by immense conflict between rival factions as part of the Western Schism, with much of Europe recognizing Clement VII, based in Avignon, as the true pope.