Adelaide of Normandy (or Adeliza) (c. 1030 – bef. 1090) was the ruling Countess of Aumale in her own right in 1069–1087. She was the sister of William the Conqueror.

Born c. 1030,[1] Adelaide was an illegitimate daughter of the Norman duke Robert the Magnificent.[2] Adelaide's brother or half-brother, Robert's son and successor William the Conqueror, was likewise illegitimate

The history of the d’Aumale family cannot be understood without a backward glance at their ancestors and their links to the royal families of France, England and even Scotland through the noble families of those kingdoms.

Before 1066 the East Riding of Yorkshire contained many scattered estates, built up piecemeal over the Anglo-Saxon period, and it was not until after the harrying of the North that it was consolidated by William the Conqueror. William granted all of Holderness (except for the church lands) as a single holding to his companion Drogo de la Beuvrière, along with many estates in Lincolnshire and manors elsewhere in England. Drogo was a Fleming, who probably came from the village of Labeuvrière near Béthune, an excellent soldier and a relative of Matilda of Flanders, the Conqueror’s wife. It is said that Drogo’s wife suffered a violent death at the hands of her husband, at which point he fled back to Flanders, as by 1087 King William had granted Holderness to Odo, the dispossessed Count de Champagne, who had arrived at the then Duke’s court in Normandy after the death of his father in c1047, on which occasion his uncle had seized his lands. Odo subsequently married William’s sister, Adelaide of Normandy, for whose support he received the “island of Holderness” and lands in Lincolnshire.

It was Adelaide who brought to the marriage the title of d’Aumale. Aumale was frontier town, often changing hands between Normandy and France until its final capture by the French in 1204, when the d’Aumale title was also confiscated, but the English kings continued to recognise it in the title of Albemarle. Adelaide and Odo passed their titles – Count d’Aumale and Lord of Holderness – to their son Stephen, but he is known to history by the former. The d’Aumale title was passed down through the generations, coming to an end with the death of Aveline in 1274.