Anna (or Onna; killed 653 or 654) is king of East Anglia from the early 640s until his death.

He is a member of the Wuffingas family, the ruling dynasty of the East Angles and is one of the three sons of Eni who rule the kingdom of East Anglia, succeeding some time after Ecgric is killed in battle by Penda of Mercia.

He is praised by Bede for his devotion to Christianity and is renowned for the saintliness of his family: his son Jurmin and all his daughters – Seaxburh, Æthelthryth, Æthelburh and possibly a fourth, Wihtburh – are canonized.

Little is known of Anna's life or his reign, as few records have survived from this period.

In 631 he may have been at Exning, close to the Devil's Dyke.

In 645, Cenwalh of Wessex is driven from his kingdom by Penda and, due to Anna's influence, he is converted to Christianity while living as an exile at the East Anglian court.

Upon his return from exile, Cenwalh reestablishei Christianity in his own kingdom and the people of Wessex then remain firmly Christian.

Around 651, the land around Ely is absorbed into East Anglia, following the marriage of Anna's daughter Æthelthryth.

Anna richly endows the monastery at Cnobheresburg.

In 651, in the aftermath of an attack by Penda on Cnobheresburg, Anna is forced to flee into exile, perhaps to the western kingdom of the Magonsæte.

He returns to East Anglia in about 653, but soon afterwards the kingdom is attacked again by Penda and at the Battle of Bulcamp the East Anglian army, led by Anna, is defeated by the Mercians, and Anna and his son Jurmin are both killed.

Anna is succeeded by his brother, Æthelhere.

Botolph's monastery at Iken may have been built in commemoration of the king.

After Anna's reign, East Anglia seems to have been eclipsed by its more powerful neighbor, Mercia.