Auguste Jean François Grenier (22 September 1814, in Andelys – 13 July 1890, in Bagnères) was a French medical doctor and entomologist.
He studied at Rouen, then at Paris where he qualified as a doctor in 1842.
The war of 1870 put an end to his research.
Grenier was especially interested in cavernicolous Coleoptera and made a large collection including the cave insect collections of Charles Nicholas Aubé (1802–1869) and of Jules Linder (1830–1869).
His collection is preserved by the Société entomologique de France.