John VIII

John VIII may refer to:
 * Pope John VIII, Pope from 872 to 882
 * Antipope John VIII, antipope in 844
 * John VIII bar Abdoun, Syriac Orthodox Patriarch of Antioch (944-1033)
 * John VIII of Constantinople, Patriarch of Constantinople (1010-1075)
 * John VIII Palaiologos, Byzantine Emperor (1392–1448)
 * John VIII, Count of Harcourt, 1398–1424
 * John VIII, Count of Vendôme, 1426–1477
 * John VIII, Archbishop of Antivari, d. 1571
 * John VIII, Count of Nassau-Siegen, 1583–1638
 * The mythical Pope Joan, in some versions of her legend