Æthelwald Moll was King of Northumbria, the historic petty kingdom of Angles in medieval England, from 759 to 765. He seized power after the murder of Oswulf son of Eadberht; his ancestry and connection to the royal family of Northumbria is unknown. Æthelwald faced at least one rebellion, led by Oswine, perhaps a brother of Oswulf. In 765 a Witenagemot of Northumbrian notables deposed Æthelwald and replaced him with Alhred, a kinsman of his predecessor. After his removal from the throne Æthelwald became a monk, perhaps involuntarily.
Æthelwald's marriage with one Æthelthryth is recorded in 762 at Catterick by Symeon of Durham. He is known to have had at least one son, Æthelred, who later became king.
Æthelwald is not recorded in the extant genealogies of Northumbrian kings, perhaps because he was not a descendant of Ida and the Bernician kings. Whether he was a descendant of the Deiran dynasty of Ælle, or simply a member of a powerful noble family, is unknown.
It is likely that he is to be identified with the patrician Moll, recorded in the reign of King Eadberht, to whom Eadberht and his brother Ecgbert, Archbishop of York granted the monasteries of Stonegrave, Coxwold, and Donaemuthe, all in modern Yorkshire. These had belonged to Moll's brother, Abbot Forthred.