Author
- Joannes Oliva2
- Johann Herolt2
- Johann Neudörffer the Elder2
- Johannes Nider2
- Johannes von Freiburg2
- John Burgh2
- John Felton2
- John Halgren of Abbeville2
- John Montgomery2
- John XXII2
- John de Beauchesne2
- John of Garland2
- John of Genoa2
- Jordan von Quedlinburg2
- Josef ibn Tabul2
- Joseph ben Gorion2
- Judah Leib Pukhovitser2
- Judah Rosanes2
- Julian of Toledo2
- Julianus Pomerius2