Earl Æthelred (d. 911) was a ruler of Mercia (c. 883 - 911). His title was "Lord of the Mercians", and he was subject to the power of Wessex.

In 886, he was given control of London by King Alfred of Wessex, whose daughter, Ethelfleda, he married.

As Alfred reconquered the Danelaw, it was useful to place the heir to the destroyed Kingdom of Mercia in control of its former area: this allowed the expansion of the Kingdom of Wessex to appear as the liberation of areas conquered by the Danes.

Aethelred was recorded as fighting many battles against the Welsh, and at one point Brochwael of Gwent appealed to Alfred for help against him. Towards the end of his life, he allowed Ethelfleda to exercise many of his powers, and when he died she succeeded him.

For context, read Lundenwic, Lundenburgh and MOLAS