Ecclesia was a word meaning "gathering of the called out ones" (or on today's terms "church") in many contexts in Ancient Greek, giving rise to many derivatives (e.g. Spanish iglesia, "church"), and can refer to:

• Ecclesia (Church), the Christian Church, which is composed of Ecclesia Militans (the "Church Militant"), and Ecclesia Triumphans (the "Church Triumphant").
• Ecclesia (ancient Athens), the popular assembly in ancient Athens.
• Ecclesia (sociology of religion), a concept in the typology of religion.
• The Ecclesia, the healing temple of The Rosicrucian Fellowship at Mount Ecclesia.