Ranulf II (also known as Ranulf de Gernon) (1099–1153) is an Anglo-Norman potentate who inherits the honor of the palatine county of Chester upon the death of his father Ranulf le Meschin, 3rd Earl of Chester.

He is descended from the Counts of [Bessin] in Normandy.

In 1136, David I of Scotland invades England as far as Durham but is forced by Stephen of England to negotiate treaties that involve granting Ranulf's lands to Scotland.

Ranulf allies himself to Matilda to further his cause.

He takes Lincoln Castle in 1141, which is retaken by Stephen in a siege in which Ranulf is forced to flee for his life.

Ranulf enlists the help of Robert, 1st Earl of Gloucester, to retake the castle and succeeds when King Stephen surrenders to him at Lincoln.

While Matilda rules England, Stephen's queen Matilda of Boulogne manages to defeat Ranulf and his allies at Winchester, which eventually results in Stephen being able to resume the throne.