- John V, King of Portugal, 1689-17501
- John, Duke of Burgundy, 1371-14191
- John, the Apostle, Saint1
- Joseph (Son of Jacob)1
- Judaism--Doctrines1
- Judges (Islamic law)1
- Judgment Day (Islam)1
- Jāmiʻ al-Muẓaffarī (Damascus, Syria)1
- Jāmiʻ al-ṣaḥīḥ (Bukhārī, Muḥammad ibn Ismāʻīl)1
- Jāmiʻ al-ṣaḥīḥ (Muslim ibn al-Ḥajjāj al-Qushayrī)1
- Kanz al-wuṣūl ilá maʻrifat al-uṣūl (Bazdawī, ʻAlī ibn Muḥammad)1
- Karaite manuscripts1
- Karaitic literature1
- Kaʻbah (Mecca, Saudi Arabia)1
- Kemalpaşazade, 1468 or 1469-15341
- Kemalpaşazade, 1468 or 1469-1534. Iṣlāḥ wa-al-īḍāḥ1
- Khabbāzī, ʻUmar ibn Muḥammad, 1231 or 1232-1292. Mughnī fī uṣūl al-fiqh1
- Khamrīyah (Ibn al-Fāriḍ, ʻUmar ibn ʻAlī)1
- Khamti language1
- Khaṭīb al-Baghdādī, Abū Bakr Aḥmad ibn ʻAlī, 1002-1071. Asmāʼ al-mubhamah fī al-anbāʼ al-muḥkamah1