Former Owner
- Joseph François René de Kergariou1
- Joseph Jekyll1
- Joseph Pope1
- Joseph Whitney1
- Joseph-Félix Allard1
- Juana I of Castile1
- Julius Hess1
- Justin MacCarthy Reagh1
- K. B. Starkie1
- Klaus Dieter Dahmen1
- Kloster Kuringen1
- Kulturhistorisches Museum Magdeburg1
- Latham family1
- Laurence Claiborne Witten II2
- Laurence Kirby1
- Laurentius van der Torqel1
- Lawrence J. Schoenberg7
- Leo S. Olschki Editore8
- Leonardo Lapiccirella2
- Leonello d'Este, Marquis of Ferrara3