Aethelhere (died November 15, 655) was a King of East Anglia (653/654–655). He was a brother of Anna of East Anglia.

Following the death of Anna at the hands of Penda of Mercia, Aethelhere became king. He participated in Penda's massive invasion of Bernicia in 655, and there is a passage in Bede's Ecclesiastical History of the English People that suggests Aethelhere was the cause of this war—auctor ipse belli—but it has been argued that an issue of punctuation in later manuscripts confused Bede's meaning on this point, and that he in fact meant to refer to Penda as being responsible for the war. When the invaders met the Bernician army under Oswiu at the Battle of Winwaed on November 15, Aethelhere fought, unlike two other prominent allies of Penda, Aethelwald of Deira and Cadfael ap Cynfeddw of Gwynedd, who deserted him. Aethelhere was killed in the battle, along with Penda.

Reference

• Prestwich, J. O. "King Æthelhere and the battle of the Winwaed", The English Historical Review, Vol. 83, No. 326. (January 1968), pages 89–95.