Author
- Jean de Wavrin1
- Jerome1
- Johann Herolt1
- Johannes de Sacrobosco1
- John Burgh1
- John Capgrave1
- John Gower1
- John Mandeville1
- John of Genoa1
- John of Seville1
- John, Duke of Berry1
- Jordan von Quedlinburg1
- Joseph Angelet1
- Joseph ben Abraham Gikatilla1
- Juana I of Castile1
- Judah ben Saul ibn Tibbon1
- Junayd ibn Sandal Baghdādī1
- Kamal Khujandi1
- Khayr al-Dīn Khalīl1
- Khvājah Muḥammad Pārsā1