Jacqueline de Longwy, Countess of Bar-sur-Seine (before 1520 – 28 August 1561), Duchess of Montpensier, Dauphine of Auvergne was a French noblewoman, and a half-niece of King Francis I of France.

On the occasion of the marriage, Jacqueline's uncle, King Francis restored the Montpensier estates and the counties of Forez, Beaujeu, and Dombes to Louis' mother.

[3] Jacqueline succeeded to the title of suo jure Countess of Bar-sur-Seine upon her mother's death, which occurred on an unknown date sometime after 1531/1538.

Three years later, in 1559, Jacqueline and her husband attended the magnificent coronation of King Francis II and Mary, Queen of Scots.

Through her daughter, Charlotte, Jacqueline was an ancestress of the House of Hanover, which reigned in Great Britain from 1714 to 1901, and from which descends the current British Royal Family.