- Idkāwī, Muḥammad. Fawāʼid al-muhimmāt fī maṭāliʻ al-awqāt1
- Ijmāʻ (Islamic law)1
- Ikmāl (Ibn Mākūlā, ʻAlī ibn Hibat Allāh)1
- Ildephonsus, Saint, approximately 610-6671
- Illegible markings1
- Illegitimacy1
- Illumination of books and manuscripts, Arab1
- Illumination of books and manuscripts, Carolingian1
- Illumination of books and manuscripts, Dutch1
- Illumination of books and manuscripts, Flemish1
- Illumination of books and manuscripts--Technique1
- Illusion (Philosophy)1
- Ilāhʹābādī, Muḥibb Allāh. Taswīyah1
- Ilāhʹābādī, ʻAbd Allāh ibn Shihāb. Sharḥ ʻalá ḍābiṭat sharāʼiṭ al-ashkāl al-arbaʻah li-Tahdhīb al-manṭiq1
- Imaginary letters1
- Immortality1
- Immortality--Christianity1
- Impediments to marriage1
- Imām al-Ḥaramayn al-Juwaynī, ʻAbd al-Malik ibn ʻAbd Allāh, 1028-1085. Burhān fī uṣūl al-fiqh1
- In Coena Domini bulls1