William Jacob Herreyns ( Antwerp, June 10 1743 - Antwerp, August 10 1827) was a Flemish painter. He is regarded as one of the last painters in the tradition of the Baroque and is the last follower of Peter Paul Rubens.
William Herreyns was a scion of a family of artists. His father, Jacob III Herreyns, was a painter and decorator. His uncle Guillaume was a sculptor. He got his initial training from these relatives. Subsequently he studied at the Academy of Antwerp where Balthasar Beschey was one of his teachers. He completed his studies in 1764 and one year later he became the director of the Academy. In 1771 he went to live in Mechelen where he founded the local Academy in 1772.
In 1797 he saved 328 paintings from the churches and monasteries that had been ordered closed by the French. Many of these paintings had in fact been stolen. He worked on the return of Rubens' paintings Our Lady with the parrot and the The Madonna surrounded by Saints. In 1810 he got permission from Napoleon to set up a museum in the former Franciscan monastery in Antwerp. In 1815 38 of the 63 pictures removed by the French were added to its collection.
His pupils included Gustave Wappers (1803 - 1874) and Antoine-Joseph Wiertz (1806 - 1865).
Herreyns' notable works include a Portrait of the artist A.C. Lens (after 1770), Godfrey, abbot of Tongerlo (1793) and John the Baptist in the Desert (1813). His work can be found in the Sint-Jan Baptist en Evangelist in Mechelen and the Royal Museum of Fine Arts in Antwerp.