John Gerrard Keulemans (June 8, 1842 - March 29, 1912) was a Dutch bird illustrator.

Keulemans worked in England from 1869. He regularly provided illustrations for The Ibis and The Proceedings of the Zoological Society. He illustrated many important bird books, including Buller's A History of the Birds of New Zealand (1873). He also spent some time collecting birds in West Africa.