Author
- John of Lancaster, 1st Duke of Bedford1
- John of Saxony1
- John of Seville ?1
- John of Wales3
- John Dokeianos1
- John, Duke of Berry1
- Jonathan Eybeschutz1
- Jordan von Quedlinburg2
- Josef ibn Tabul2
- Joseph Albaradani1
- Joseph Angelet1
- Joseph Haslewood1
- Joseph Nasi1
- Joseph Trani1
- Joseph Yitzchak Hakohen Poppers1
- Joseph ben Abraham Gikatilla8
- Joseph ben Ephraim Karo4
- Joseph ben Gorion2
- Joseph ben Judah ibn Aknin1
- Joseph ben Moses Sarfati1