Ilisia (Greek: Ιλίσια pronounced [iˈli.si.a]) is a neighborhood of Athens, Greece, named after the river Ilisos.

A portion of the neighborhood, Ano Ilisia (Upper Ilisia), is in Zografou and is near the Theology, Philosophy and Scientific faculties of the University of Athens.

Ilisia is named after the Ilisos river, which rises near Kaisariani on the slopes of Mount Hymettus and which, although Athens' historic river, is barely noticeable except in heavy rain.

Although the name Ilisiakos seems to mean "team of Ilisia", the spelling, with Greek letter H (Ηλυσιακός) instead of I (Ιλισιακός), refers to Elysium (Ἠλύσιον πεδίον).

The rationale for this is that the club aims to represent a wider area from Ilisia.