Diuma was a 7th-century Irish missionary and the first bishop of the Anglo-Saxon kingdom of Mercia. Following the conversion of Peada, the son of King Penda, Diuma traveled from Northumbria to the Mercian region in 653 alongside three other priests. He was consecrated as a bishop by Finan after the death of Peada. Although historical records regarding his exact location and the specific boundaries of his diocese are imprecise, he is credited with helping to establish the Christian faith among the Mercians and the Middle Angles.