Adrian V (also known as Hadrian V), born Ottobuono de' Fieschi (ca. 1205–August 18, 1276), pope in 1276, was a Genoese who was created cardinal deacon of San Adriano by his uncle Innocent IV.
He was sent to England in 1265 by Clement IV to mediate between King Henry III and his barons, and to preach the Crusades; he remained there for several years as the papal legate.
He was elected pope to succeed Innocent V on July 11, 1276, but died at Viterbo on August 18, without ever having been ordained to the priesthood.