Morcar (or Morkere) (d. 1087) was the son of Aelfgār, Earl of Mercia and brother of Edwin. He was himself the Earl of Northumbria from 1065 to 1066, when he was replaced by William the Conqueror with Copsig.
In 1065, the Northumbrians revolted against their Earl Tostig, who was replaced by Morcar and declared an outlaw. In 1066 Tostig invaded Mercia, after mounting raids further south, but was repulsed by Edwin and Morcar and fled to Scotland. Later in the year he returned to Northumbria with the army of King Harald Hardrada of Norway. Morcar and Edwin resisted and inflicted heavy losses on the invaders, but suffered a severe defeat at the Battle of Fulford.
After the death of Harold Godwinson at the Battle of Hastings, Edwin and Morcar threw their support behind the Edgar the Atheling, who was proclaimed king, but they failed to muster an effective military response to the invading forces of William of Normandy and soon submitted. In 1068 they raised a revolt in Mercia, but rapidly capitulated when William advanced against them.
Though they were pardoned, they again turned against William early in 1071. Edwin was soon betrayed and killed, while Morcar joined the rebellion, initiated by Thurstan, Abbot of Ely and tactically organized by Hereward the Wake, against William the Conqueror at the Isle of Ely. When the island was opened to the Normans, Morcar was captured and imprisoned. He remained in captivity until William's death in 1087, when the dying king ordered the release of all his prisoners. After a brief period at liberty, Morcar was again imprisoned by William II Rufus and died in captivity.