- John II, King of Aragon, 1397-14791
- John IV, King of Portugal, 1604-16561
- John Manuel, Prince of Portugal, 1537-15541
- John V, King of Portugal, 1689-17501
- John, King of England, 1167-12161
- Jonah (Biblical prophet)1
- Joseph (Son of Jacob)1
- Judaism--Liturgy--Texts1
- Jugurthine War (111-105 B.C.)1
- Julian, of Eclanum, Bishop, 380-approximately 4551
- Justa, Saint, -approximately 2871
- Justinian I, Emperor of the East, 483?-5651
- Karo-Batak dialect1
- Khaṭīb al-Baghdādī, Abū Bakr Aḥmad ibn ʻAlī, 1002-1071. Tārīkh Baghdād1
- Knights of Malta1
- Knotesford, John, -15891
- Krishna (Hindu deity)--Early works to 18001
- Krishna (Hindu deity)--Poetry1
- Kyi︠e︡vo-Pechersʹka lavra1
- Kāfiyah (Ibn al-Ḥājib, ʻUthmān ibn ʻUmar)1