Gregorio Tarquini (died 1145) was an Italian cardinal of the Roman Catholic Church. Born in Rome, he was created cardinal deacon of Sts. Sergio e Bacco in December 1122. He participated in five papal elections: those of 1124 ( Honorius II), 1130 ( Innocent II, whom he supported against Anacletus II), 1143 ( Celestine II), 1144 ( Lucius II) and 1145 ( Eugenius III).