Æthelwold () or Æthelwald (died 902 or 903) was the younger of two known sons of Æthelred I, King of Wessex from 865 to 871. Æthelwold and his brother Æthelhelm were still infants when their father the king died while fighting a Danish Viking invasion. The throne passed to the king's younger brother (Æthelwold'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.