Eugène Michel Antoniadi (Greek: Ευγένιος Αντωνιάδης; 1 March 1870 – 10 February 1944) was a Greek-French astronomer.

Antoniadi was born in Istanbul (Constantinople) but spent most of his adult life in France after being invited there by Camille Flammarion.

That same year, Henri Deslandres, Director of the Meudon Observeratory, provided him with access to the Grande Lunette (83-cm Great Refractor) [5] He became a highly reputed observer of Mars, and at first supported the notion of Martian canals, but after using the 83 centimeter telescope at Meudon Observatory during the 1909 opposition of Mars, he came to the conclusion that canals were an optical illusion.

Antoniadi was a prolific writer of articles and books (the Astrophysics Data System lists nearly 230 that he authored or co-authored).

He frequently wrote articles for L'Astronomie of the Société astronomique de France, Astronomische Nachrichten, and the Monthly Notices of the Royal Astronomical Society, among others.