The official inauguration of Athens College took place on October 18, 1925. October 18 is designated “Athens College Founders' Day”, to commemorate the great founders and benefactors of the School, Emmanuel Benakis, Stephanos and Penelope Delta and many more enlightened Greeks and American philhellenes.

Celebrations for the day begin with a liturgy at the Church of the Archangels followed by celebratory events in all school units.