Judith of Flanders (or Judith of France) (c. 843 – c. 870) is the eldest daughter of the Frankish King and Holy Roman Emperor Charles the Bald and his wife Ermentrude of Orléans.

Through her marriages to two Kings of Wessex, Æthelwulf and Æthelbald, she is twice a queen.

Her first two marriages ware childless, but through her third marriage to Baldwin, she becomes the first Countess of Flanders and an ancestress of later Counts of Flanders.

One of her sons by Baldwin marries Ælfthryth, a daughter of Æthelbald's brother, Alfred the Great.

She is also an ancestress of Matilda of Flanders, the consort of William the Conqueror, and thus of later monarchs of England.