Former Owner
- Lathrop Colgate Harper1
- Laura Hurd Motion1
- Laurence Kirby1
- Law Society1
- Lawrence J. Schoenberg18
- Leicester Harmsworth1
- Leo Olschki3
- Leonardus Martinotius1
- Leonello d'Este, Marquis of Ferrara2
- Librairie Tross1
- Lionel Tollemache, 4th Earl of Dysart1
- Lodovicus Saltariellus1
- London School of Jewish Studies2
- Long Island Historical Society, Maine1
- Louis Bourguet1
- Louis Charles Elson1
- Louis César de La Baume Le Blanc3
- Louis Thompson Rowe1
- Louis XII of France1
- Louis XIV of France1