Andrzej Jerzy Mniszech was a Polish painter and art collector.
His father was Karol Filip Wandalin Mniszech (1794–1844), and his mother Eleonora Cetner (1798–1871). His paternal grandfather was Michał Jerzy Mniszech, a Polish nobleman who was Grand Marshal of the Crown during the reign of Stanisław II Augustus. He spent his youth in the family palace in Wiśniowiec and Paris. In 1846 he inherited a lot of debts, and when he moved with his wife, Anna Elżbieta Potocka (1827–1885) and his son Leon (1849–1901) to Paris in 1854, he took with him a large part of the private family collections from Wiśniowiec, especially paintings. The palace the couple acquired in 1861 at Rue Daru 16 in Paris was owned by his wife, and after her death in 1885, it was owned by their son Leon. The entire collection counted about 500 paintings, engravings, drawings, ceramics and furniture. He collected mainly the Dutch masters of the 17th century and the French artists of the Rococo period; he was one of the first amateurs and collectors of Frans Hals's works. The collection was dispersed twice: in 1902 because of his son Leon's death, and in 1910 when the collection went up for an auction.
He was active in Paris during the years 1854–1905. He started learning drawing with his brother Jerzy in Wiśniowiec, in the 1860s he continued in Paris, studying with Jean Gigoux and Leon Cogniet. He painted mainly portraits and used the form of a triptych.