Jean-Baptiste Regnault (9 October 1754 – 12 November 1829) was a French painter.
Regnault was born in Paris, and began life at sea in a merchant vessel. At the age of fifteen his talent attracted attention, and he was sent to Italy by M. de Monval under the care of Bardin. After his return to Paris, Regnault, in 1776, won the Grand Prix for his painting Alexandre and Diogène, and in 1783 he was elected Academician. His diploma picture, the Education of Achilles by Chiron, is now in the Louvre, as also the Christ taken down from the Cross, originally executed for the royal chapel at Fontainebleau, and two minor works – the Origin of Painting and Pygmalion praying Venus to give Life to his Statue.
Besides various small pictures and allegorical subjects, Regnault was also the author of many large historical paintings; and his school, which reckoned amongst its chief attendants Guérin, Crepin, Lafitte, Blondel, Robert Lefèvre, Henriette Lorimier and Menjaud, was for a long while the rival in influence of that of David.
Besides Merry-Joseph Blondel, Pierre-Narcisse Guérin, Robert Lefèvre, and Henriette Lorimier, Jean-Baptiste Regnault's students include: Godefroy Engelmann, Louis Hersent, Charles Paul Landon, Hippolyte Lecomte, Jacques Réattu, Jean-Hilaire Belloc.
Jean-Baptiste Regnault was married first to Sophie Meyer, then Sophie Félicité Beaucourt.
His burial place is Père-Lachaise Cemetery.