- Hadith--Terminology3
- Ibn Abī Jumhūr al-Aḥsāʼī, Muḥammad ibn ʻAlī, -approximately 1473. Masālik al-afhām3
- Ibn al-Najjār, Taqī al-Dīn Muḥammad ibn Aḥmad, 1492 or 1493-1564 or 1565. Mukhtaṣar al-Taḥrīr3
- Illumination of books and manuscripts, Arab3
- Illumination of books and manuscripts, Iranian3
- Imamate3
- Interest (Islamic law)3
- Iqnāʼ (Ḥujāwī, Mūsá ibn Aḥmad)3
- Isfarāyīnī, Muḥammad ibn Muḥammad, -1285. Ḍawʼ al-Miṣbāḥ3
- Islam and politics3
- Islamic calendar3
- Islamic poetry3
- Islamic sects3
- Iṣfahānī, Maḥmūd ibn ʻAbd al-Raḥmān, 1275 or 1276-1348 or 1349. Maṭāliʻ al-anẓār3
- Jaʻbarī, Ibrāhīm ibn ʻUmar, 1242 or 1243-1331 or 1332. Wāḍiḥah fī tajwīd al-Fātiḥah3
- Kaydānī. Fiqh al-Kaydānī3
- Khabbāzī, ʻUmar ibn Muḥammad, 1231 or 2-1292. Mughnī fī uṣūl al-fiqh3
- Khiḍr (Legendary character)3
- Kinship (Islamic law)3
- Knowledge, Theory of (Islam)3