Marie-Louise O'Murphy de Boisfaily (21 October 1737 in Rouen – 11 December 1814 in Paris) was one of the younger mistresses of King Louis XV of France. Her original surname is also given in sources as Murphy, Morphy, or O'Morphy, and she is sometimes referred to as "La Morphise" or "La Belle Morphise".
She was the seventh and youngest child of Daniel O’Murphy de Boisfaily, an Irish officer who had taken up shoemaking in Rouen, France, and his wife Marguerite Igny. After the death of her father in 1753, her mother brought the family to Paris.
In his Histoire de ma vie (vol. 3, chap. 11), Giacomo Casanova relates that he found her "a pretty, ragged, dirty, little creature" of thirteen years in the house of her actress sister. Struck by her beauty when seeing her naked, however, he had a nude portrait of her painted, with the inscription "O-Morphi" (punning her name with Modern Greek ὄμορφη, "beautiful"), a copy of which found its way to the King, who took her as one of his mistresses. (This portrait is apparently not to be identified with the memorable and provocative portrait by François Boucher, though Casanova's description indicates that the poses were similar.)
She quickly became a favourite, and, after a miscarriage in 1753 (which apparently deeply affected the King), she gave birth to Louis XV's illegitimate daughter, Agathe Louise de Saint-Antoine, born in Paris on 20 May 1754 and baptized that same day at Saint-Paul. At the age of 19, Agathe married René Jean de la Tour du Pin, marquis de la Charce (born Paris, 26 July 1750), at the Parisian Convent of the Visitation. But Agathe died after only nine months of marriage, on 6 September 1774, as consequence of a miscarriage. Her widower remarried and had a son, but died young in 1781.
After serving as a mistress to the King for just over two years, O'Murphy made a mistake that was common for many courtesans, that of trying to replace the official mistress. Around 1754, she unwisely tried to unseat the longtime royal favorite, Madame de Pompadour. This ill-judged move quickly resulted in O'Murphy's downfall at court. A marriage was arranged to Jacques Pelet de Beaufranchet, seigneur d'Ayat (born 5 March 1728), which took place on 27 November 1755 in Paris. From this union, the former royal mistress had two children: the first one, a daughter, Louise Charlotte Antoinette Françoise (born 30 October 1756 - died 6 February 1759), died in infancy. Jacques de Beaufranchet was killed in action on 5 November 1757, at the battle of Rossbach, seventeen days before the birth of their second child, a son, Louis Charles Antoine Pelet (born 22 November 1757 - died 2 July 1812), the later comte de Beaufranchet and General under the Republic.
Two years later, on 19 February 1759 at Riom, O'Murphy married again to François Nicolas Le Normant, comte de Flaghac (born 13 September 1725), a widower with three children. From this union, O'Murphy gave birth to a daughter, Marguerite Victoire (born 5 January 1768 - died 1814), who, according to one theory, could be another illegitimate daughter of Louis XV.
François Le Normant died on 24 April 1783. She was accorded a pension of twelve thousand francs. 
During the Reign of Terror she was imprisoned as a 'suspect,' under the name of O'Murphy, at Sainte-Pelagie and at the English Benedictine convent in Paris. On her release she married Louis Philippe Dumont, (born 17 November 1765 - died 11 June 1853), twenty-eight years younger than her. This union quickly failed, and after almost three years, they divorced on 16 March 1798. O'Murphy never married again.
Marie Louise died at Paris 11 December 1814.
Her son, General Beaufranchet, has been taken by some writers for her child by Louis XV, but that child was probably brought up under an assumed name, and Beaufranchet was most likely the issue of her first marriage. He was a royal page in 1771, lieutenant of infantry in 1774, was probably present as chief of Berruyer's staff at Louis XVI's execution, and served as brigadier-general in Vendee. Suspended as a ci-devant in July 1793, he addressed remonstrances to the minister of war, excusing himself for having been born in a class justly disliked, and mentioning his mother, then at Havre with her grandchildren, but making no reference to his father. Through the influence of Louis Desaix, his cousin, he was in 1798 allowed a retiring pension ; he sat in the Corps Legislatif in 1803, and died at Paris 2 July 1812.
- René Rouault de la Vigne, "Les soeurs Morphy de Rouen à Paris et Versailles".
- Giacomo Casanova, History of My Life, vols. 3 & 4, trans. Willard R. Trask (New York: Harcourt, 1967), pp. 198–202.
- Comte de Fleury, "Louis XV intime et les petites maîtresses".
- Camille Pascal, "Le goût du roi : Louis XV et Marie-Louise O'Murphy". This theory is supported by three facts: 1. The King gave Marie-Louise O'Murphy the sum of 350,000 livres between 1771-1772 (Marguerite, then a three-years-old child, surpassed the dangerous first year of infancy, and Louis XV probably wanted to protect the mother of his child), 2. When Marguerite married in 1786 all the royal family was present and signed the marriage contract, and 3. After the Bourbon Restoration, King Charles X gave Marguerite an "annual indemnity" from his own treasure.
- Alger 1894.
This article incorporates text from a publication now in the public domain: Alger, John Goldworth (1894). "Murphy, Marie Louise". In Lee, Sidney. Dictionary of National Biography 38. London: Smith, Elder & Co.