Pope Gregory IV (Latin: Gregorius IV) was Pope from October 827 to his death in 844. His pontificate was notable for the papacy’s attempts to intervene in the quarrels between the emperor Louis the Pious and his sons. It also saw the breakup of the Carolingian Empire in 843.

Gregory IV died on January 25, 844, and was buried in St. Peter’s Basilica. He was succeeded by Pope Sergius II.