Ethelbald (or Æthelbald) of Mercia (d. 757) was a king of Mercia (ruled 716 - 757) in England and a Bretwalda.

Little is known about his reign. Boniface, bishop of Mainz, wrote him a letter, in either 746 or 747, that reproached him for his behavior towards church property, towards nuns, and concerning the example he set for his subjects. He was killed in the night by his body-guard in Seckington near the royal seat of Tamworth, possibly due to a feud.

Preceded by:
Oswiu of Northumbria
List of British monarchs Succeeded by:
Offa of Mercia