Joseph-Nicolas Robert-Fleury was a French painter. Born in Cologne, he was sent by his family to Paris, and after travelling in Italy returned to France and made his first appearance at the Salon in 1824; his reputation, however, was not established until three years later, when he exhibited Tasso at the Convent of Saint Onophrius.

Endowed with a vigorous original talent, and with a vivid imagination, especially for the tragic incidents of history, he soon rose to fame, and in 1850 succeeded François Granet as member of the Académie des Beaux-Arts. In 1855, he was appointed professor and in 1863 director of the École des Beaux-Arts, and in the following year he went to Rome as director of the French Academy in that city. His pupils included Marie-Adélaïde Baubry-Vaillant, David Bles, Marguerite Jacquelin, Charles Désiré Hué [fr], Leon Kapliński and Henri Le Riche [fr]. His son, Tony Robert-Fleury, was also a painter.