Author
- Isabella I of Castile1
- Isaiah di Trani1
- Isidore of Seville1
- Iskandar Rūmī1
- Ismail bin Mohammad Rizi1
- Ismāʻīl Jarrāḥī1
- Ismāʻīl ibn Aḥmad Ibn al-Athīr1
- Ismāʻīl ibn Ghunaym Jawharī1
- Ismāʻīl ibn Luṭf Allāh Bākharzī1
- Ismāʻīl ibn Muḥammad Māzandarānī1
- Ismāʻīl ibn Sinān Sīwāsī1
- Ismāʻīl Ḥaqqī Āsikjīʹzādah1
- Issachar ben Mordecai ibn Susan1
- Izz al-Din ibn 'Abd al-Salam1
- Izzatullah Bengali1
- Jabir ibn Hayyan1
- Jacob Jacobke Heilprin1
- Jacob ben Asher1
- Jacob ben Jacob, ha-Kohen, -approximately 12701
- Jacob ben Machir ibn Tibbon1