Françoise de Foix, Comtesse de Châteaubriant (c. 1495 – 16 October 1537) was a mistress of Francis I of France.
Françoise was the daughter of Jean de Foix, Vicomte de Lautrec, and Jeanne d'Aydie. Her father was the son of Pierre de Foix, Vicomte de Lautrec; Pierre had been a younger brother of Gaston IV of Foix, who had married Leonor, Queen of Navarre. Françoise was thus a second cousin of the Duchess of Brittany and Queen of France, Anne, whose mother had been a daughter of Gaston IV and Leonor. Françoise was brought up at Anne's court, where she met Jean de Laval, count of Châteaubriant, to whom she was engaged in 1505. On 11 March 1508 she gave birth to a daughter, Anne, who unfortunately died on 12 April 1521. The couple formally married in 1509, living together at Châteaubriant until Francis I called them at court in 1516. Tall and dark-haired, she was also cultured, spoke Latin and Italian, and wrote poetry.
Upon arriving at the royal court, Françoise's attributes and gifts made her alluring to the equally gifted and cultured King, who promptly attempted to seduce her. He began to give favours and gifts to her family. Her husband became a commander of a company. Her elder brother, the Viscount of Lautrec, received the charge of governor of the Milanese duchy. Her two other brothers, Thomas, lord of Lescun, and André, lord of Lesparre or Asparros, were also promoted to high positions in the military by the king. Françoise eventually became the mistress of the king, after a period of resistance, circa 1518.
On 25 April 1519 the Dauphin François was baptised at Amboise. Jean de Châteaubriant and his wife assisted in the ceremony, and Françoise was placed near to the royal princesses, which signified to the Court that she was La mye du roi ("The Sweetheart of the King"). She was the first official mistress that Francis had taken, and he made his affections for her plain to the Court, against her wishes. This greatly displeased his mother, Louise of Savoy, who disliked the de Foix family.