The Gennadius Library (Greek: Γεννάδειος Βιβλιοθήκη), also known as the Gennadeion, is one of the most important libraries in Greece, with over 110,000 volumes on Greek history, literature and art from Antiquity until modern times. The library is located at Souidias Street 61, on the slopes of Mount Lycabettus, in central Athens.
The library is one of the two belonging to the American School of Classical Studies at Athens (along with the Blegen Library).