- Italy--Vercelli1
- Jamʻ bayna al-ṣaḥīḥayn (Ḥumaydī, Muḥammad ibn Fattūḥ)1
- Jewish prayers for rain1
- Jewish religious poetry, Hebrew1
- Jihad1
- Jinn1
- Jāmiʻ al-Muẓaffarī (Damascus, Syria)1
- Jāmiʻ al-uṣūl li-aḥādīth al-Rasūl (Ibn al-Athīr, Majd al-Dīn al-Mubārak ibn Muḥammad)1
- Jāmiʻ al-ṣaghīr (Suyūṭī)1
- Karaite law1
- Karaites (Jewish law)1
- Karaitic literature1
- Karmī, Marʻī ibn Yūsuf, -1623 or 16241
- Karshuni1
- Khiḍr (Legendary character)1
- Khulāṣat al-ḥisāb (ʻĀmilī, Bahāʼ al-Dīn Muḥammad ibn Ḥusayn)1
- Khuzāʻī, Diʻbil ibn ʻAlī, 765 or 766-860 or 861. Qaṣīdah1
- Kinship (Islamic law)1
- Knowledge, Theory of (Islam)1
- Kumayl ibn Ziyād, 633 or 634-7011