The Second Council of Nicaea is recognized as the last of the first seven ecumenical councils by the Eastern Orthodox Church and the Catholic Church. In addition, it is also recognized as such by the Old Catholics and others. Protestant opinions on it are varied.

It met in AD 787 in Nicaea (site of the First Council of Nicaea; present-day İznik in Turkey) to restore the use and veneration of icons (or, holy images), which had been suppressed by imperial edict inside the Byzantine Empire during the reign of Leo III (717–741). His son, Constantine V (741–775), had held the Council of Hieria to make the suppression official.