- Ijtihād (Islamic law)1
- Imaginary letters1
- Immortality--Islam1
- Imām al-Ḥaramayn al-Juwaynī, ʻAbd al-Malik ibn ʻAbd Allāh, 1028-1085. Burhān fī uṣūl al-fiqh1
- Imāmʹzādah, Muḥammad ibn Abī Bakr, 1097 or 1098-1177 or 1178. Shirʻat al-Islām1
- Intention--Religious aspects--Islam1
- Interpersonal relations--Religious aspects--Islam1
- Iran--Dāmghān1
- Iran--Kirmān1
- Iran--Tabrīz1
- Isbījābī, Aḥmad ibn Manṣūr, -approximately 1087. Sharḥ al-Mukhtaṣar fī al-fiqh1
- Islam and politics1
- Islam--Apologetic works1
- Islamic cosmology1
- Islamic poetry, Arabic1
- Islamic sermons, Arabic1
- Isra' and Mi`raj of the Prophet Muhammad1
- Jamʻ al-jawāmiʻ fī al-uṣūl (Subkī, Tāj al-Dīn ʻAbd al-Wahhāb ibn ʻAlī)1
- Jaʻbarī, Arslān ibn Yaʻqūb, -1300. Risālat al-tawḥīd1
- Jidd Ḥafṣī, ʻAlī ibn Luṭf Allāh, active 17th century-18th century1