Louise Françoise de la Vallière (August 6, 1644 – 1710), was mistress to Louis XIV of France from 1661 to 1667.

Louise was born at Tours, the daughter of an officer, Laurent de la Baume le Blanc, who took the name of La Vallière from a small property near Amboise. Laurent de la Vallière died in 1651; his widow soon married again, and joined the court of Gaston d'Orléans at Blois. Louise was brought up with the younger princesses, the step-sisters of "La Grande Mademoiselle". After Gaston's death his widow moved with her daughters to the palace of the Luxembourg in Paris, and with them went Louise, aged sixteen. Through the influence of a distant kinswoman Mme de Choisy, she was named maid of honor to Henrietta, sister of King Charles II of England, who was about her own age and had just married Philippe I of Orléans, the King's brother. Henrietta joined the court at Fontainebleau in 1661, and was soon on friendly terms with her brother-in-law, resulting in some scandal. To avoid this, it was decided that Louis should pay court elsewhere, and Louise was selected. She had only been at Fontainebleau for two months before she became the king's mistress. The affair, begun as a blind, quickly developed into real passion on both sides. It was Louise's first serious attachment and she was an innocent, religious-minded girl who brought neither coquetry nor self-interest to their secret relationship. Nicolas Fouquet's curiosity in the matter was one of the causes of his disgrace.

In February 1662 there was a storm when Louise refused to tell her lover about the affair between Madame (Henrietta) and the comte de Guiche. She fled to an obscure convent at Chaillot, where Louis rapidly followed her. Her enemies, chief of whom was Olympe Mancini, comtesse de Soissons, Mazarin's niece, sought her downfall by bringing her liaison to the ears of Queen Marie-Thérèse. She was removed from the service of Madame, and established in a small building in the Palais Royal, where in December 1663 she gave birth to a son, Charles, who was given in charge to two faithful servants of Colbert. Concealment was practically abandoned after her return to court, and within a week of Anne of Austria's death in January 1666, La Vallière appeared at mass side by side with Marie-Thérèse. But her favor was already waning. She had given birth to a second child in January 1665, but both children were dead before the autumn of 1666. A daughter born at Vincennes in October 1666, who received the name of Marie Anne and was known as Mlle de Blois, was publicly recognized by Louis as his daughter in letters-patent making Louise a duchess in May 1667 and conferring on her the estate of Vaujours. In October of that year she bore a son, but by this time her place in Louis's affections had been usurped by Madame de Montespan, her long-standing rival. She was compelled to remain at court as the king's official mistress, and even to share Mme de Montespan's apartments at the Tuileries. She tired to leave in 1671, fleeing to the convent of Ste Marie de Chaillot, only to be compelled to return. In 1674 she was finally permitted to enter the Carmelite convent in the Rue d'Enfer under the name of Sister Louise of the Misericord. She took the final vows a year later. She died in 1710 in Paris.

Her daughter married Armand de Bourbon, prince of Conti, in 1680. The count of Vermandois, her youngest child, died on his first campaign at Courtrai in 1683.

La Vallière's Reflexions sur la miséricorde de Dieu, written after her retreat, were printed by Lequeux in 1767, and in 1860 Réflexions, lettres et sermons, by M. P. Clement (2 vols.). Some apocryphal Memoires appeared in 1829, and the Lettres de Mme la duchesse de la Vallière (1767) are a corrupt version of her correspondence with the maréchal de Bellefonds.

The term lavalliere, the name for a jewelled pendant necklace, comes from her name.

Her life was the basis for a character in Alexandre Dumas's novel The Vicomte de Bragelonne.de:Louise de La Vallière fr:Louise de La Vallière