Étienne de La Vallée Poussin, also called Delavallée-Poussin in certain biographies, was a French history painter and creator of interior decorative schemes.

Related on his mother's side to the family of the great painter Nicolas Poussin, La Vallée-Poussin was born in Rouen, where he attended the école des Beaux-Arts, under Descamps, and made rapid progress in his studies. After having been one of the top laureates of the school three times, he went to Paris to perfect his art. Welcomed into the workshop of Jean-Baptiste Marie Pierre, the royal painter, he won the 1759 1e prix de l'Académie Royale de peinture et de sculpture and set off for Italy.

La Vallée-Poussin spent many years in Rome, where he was admitted to the Maltese order with the rank of "Cavalier Donato" (i.e. not of noble lineage, but given for services rendered to the order) and where he became a member of the Academy of Arcadia. On his return to France, he was in 1789 admitted to the Académie de Peinture, with a tableau de réception entitled Return of the young Tobias and his meeting his mother and father. He died in Paris.