Beornwulf (died 826) was the King of Mercia, a kingdom of Anglo-Saxon England, from 823 until his death in 826.

His short reign saw the collapse of Mercia's supremacy over the other kingdoms of the Anglo-Saxon Heptarchy.

[6] However, Beornwulf may be distantly related to a prior Mercian king, Beornred, as well as two subsequent rulers, Beorhtwulf and Burgred— all members of the so-called B-dynasty or group.

That same year, Ecgberht's son Æthelwulf invaded Kent and drove out its pro-Mercian king, Baldred.

Beornwulf rebuilt the Abbey of St. Peter (later Gloucester Cathedral)[10] and he presided over two synods at Clofesho (an unknown location believed to be near London with Archbishop Wulfred of Canterbury, in 824 and 825.