Wulfhere or Wulfar (died 675) is King of Mercia from 658 until 675.

He is the first Christian king of all of Mercia, though it is not known when or how he converted from Anglo-Saxon paganism.

His accession marks the end of Oswiu of Northumbria's overlordship of southern England, and Wulfhere extendshis influence over much of that region.

His campaigns against the West Saxons lead to Mercian control of much of the Thames valley.

He conquers the Isle of Wight and the Meon valley and gives them to King Æthelwealh of the South Saxons.

He also has influence in Surrey, Essex, and Kent.

He marries Eormenhild, the daughter of King Eorcenberht of Kent.

Wulfhere's father, Penda, is killed in 655 at the Battle of Winwaed, fighting against Oswiu of Northumbria.

Penda's son Peada becomes king under Oswiu's overlordship but is murdered a year later.

Wulfhere comes to the throne when Mercian nobles organize a revolt against Northumbrian rule in 658 and drive out Oswiu's governors.

By 670, when Oswiu dies, Wulfhere is the most powerful king in southern Britain.

He is effectively the overlord of Britain south of the Humber from the early 660s, although not overlord of Northumbria as his father had been.

In 674, he challenges Oswiu's son Ecgfrith of Northumbria, but is defeated.

He dies, probably of disease, in 675.

Wulfhere is succeeded as King of Mercia by his brother, Æthelred.

Stephen of Ripon's Life of Wilfrid describes Wulfhere as "a man of proud mind, and insatiable will".