Ęthelwold or Ęthelwald (died 902 or 903) was the younger of two known sons of Ęthelred I, King of Wessex from 865 to 871. Because Ęthelwold ętheling and his brother were still infants when their father the king died while fighting a Danish Viking invasion, the throne passed to the king's younger brother (and Ęthelwold's uncle) Alfred the Great, who carried on the war against the Vikings and won a crucial victory at the Battle of Edington in 878.
After Alfred's death in 899, Ęthelwold disputed the throne with Alfred's son, Edward the Elder. As senior ętheling (prince of the royal dynasty eligible for kingship), Ęthelwold had a strong claim to the throne. He attempted to raise an army to support his claim, but was unable to get sufficient support to meet Edward in battle and fled to Viking-controlled Northumbria, where he was accepted as king. In 901 or 902 he sailed with a fleet to Essex, where he was also accepted as king.
The following year Ęthelwold persuaded the East Anglian Danes to attack Edward's territory in Wessex and Mercia. Edward retaliated with a raid on East Anglia, and when he withdrew the men of Kent lingered and met the East Anglian Danes at the Battle of the Holme. The Danes were victorious but suffered heavy losses, including the death of Ęthelwold, which ended the challenge to Edward's rule.