- Ji bu--Bie ji lei--Yuan1
- Ji bu--Zong ji lei--Cong bian1
- Jihad1
- Jinn1
- John I, King of Portugal, 1357-14331
- John VIII Palaeologus, Emperor of the East, 1392-14481
- John the Baptist's Day1
- Joseph Della Reina, active 15th century1
- Juana, of Austria, Princess of Portugal, 1535-15731
- Judges (Islamic law)1
- Judicial power (Islamic law)1
- Julius III, Pope, 1487-15551
- Jurjānī, ʻAlī ibn Muḥammad, al-Sayyid al-Sharīf, 1340-14131
- Jurjānī, ʻAlī ibn Muḥammad, al-Sayyid al-Sharīf, 1340-1413. Miṣbāḥ fī sharḥ al-Miftāḥ1
- Jurjānī, ʻAlī ibn Muḥammad, al-Sayyid al-Sharīf, 1340-1413. Ḥāshiyah ʻalá Sharḥ Mukhtaṣar al-Muntahá1
- Jāmiʻ al-ṣaḥīḥ (Muslim ibn al-Ḥajjāj al-Qushayrī)1
- Jāmī, 1414-1492. Risālah-i muʻammā1
- Jārbardī, Fakhr al-Dīn Aḥmad ibn al-Ḥasan, d. 1345. Mughnī fī ʻilm al-naḥw1
- Kamāl al-Dīn Muḥammad ibn Muḥammad, -1418. Naẓm Nukhbat al-fikar fī muṣṭalaḥ ahl al-athar1
- Karma1