Jean Chacornac (June 21, 1823 – September 23, 1873) was a French astronomer.
He was born in Lyon and died in St Jean en Royans. Working in Marseille and Paris, he discovered six asteroids and the comet Chacornac C/1852 K1 which may be the source of the current Eta Eridanids meteors. The asteroid 1622 Chacornac and the crater Chacornac on the Moon are named in his honour. Awarded the Lalande Prize in 1855 and 1856.