Adeliza of Louvain (1103-1151) was queen consort of England from 1121 to 1135, the second wife of King Henry I of England. She was the daughter of a French Count, Godfrey of Louvain.

She married King Henry I in 1121 when she is thought to have been aged somewhere between fifteen and eighteen; he was fifty three. It is believed that Henry's only reason for marrying again was his desire for a male heir. (Despite holding the record for the largest number of illegitimate children of any British monarch, Henry's only legitimate male heir had died in 1120.) Adeliza was reputably quite pretty, and Louvain and England had a mutual enemy in Flanders; these were the likely reasons she was chosen. However, no children were born during the almost 15 years of the marriage.

When her husband died in 1135, Adeliza lived as a nun at Wilton, near Salisbury. As she was still young she came out of mourning some time before 1139 and married William d'Albini, who had been one of Henry's chief advisors. She brought with her a queen's dowry, including the great castle of Arundel, and King Stephen created d'Albini Earl of Arundel. Seven of their children were to survive. Among the descendants of this marriage came two girls destined to become tragic queens; Anne Boleyn and Catherine Howard. Adeliza spent her final years in Flanders in a convent.

One of Adeliza's brothers, Jocelin, came to England and married Agnes de Percy, heiress of the Percy family. Their children took their mother's name, and their descendants include the medieval Earls of Northumberland.