- Isra' and Mi`raj of the Prophet Muhammad1
- Israel--Acre1
- Izmīrī, Muṣṭafá ibn Rajab, active 17th century1
- Jamʻ al-jawāmiʻ fī al-uṣūl (Subkī, Tāj al-Dīn ʻAbd al-Wahhāb ibn ʻAlī)1
- Judgment Day (Islam)1
- Jumʻah1
- Jāmiʻ al-Qarawīyīn (Fès, Morocco)1
- Jāmiʻ al-ṣaḥīḥ (Bukhārī, Muḥammad ibn Ismāʻīl)1
- Jīlī, ʻAbd al-Karīm ibn Ibrāhīm, 1365 or 1366- Insān al-kāmil fī maʻrifat al-awākhir wa-al-awāʼil1
- Kabāʼir (Muḥammad ibn ʻAbd al-Wahhāb)1
- Karaite law1
- Karaite manuscripts1
- Kashshāf (Zamakhsharī, Maḥmūd ibn ʻUmar)1
- Kaʻbah (Mecca, Saudi Arabia)1
- Kemalpaşazade, 1468 or 1469-15341
- Kings and rulers1
- Kisāʼī, ʻAlī ibn Ḥamzah, -804 or 8051
- Knowledge, Theory of (Islam)1
- Language and languages--Philosophy1
- Laylat al-Qadr2