- Corliss Lamont: Named a Humanist Fellow by the American Humanist Association in 1970.[53]
- Stieg Larsson: Swedish leftist journalist, feminist, novelist and atheist, author of Millenium series of novels.
- Norman Lear: Presented the Humanist Arts Award 1977 by the American Humanist Association.[54]
- Simon Le Bon (born 1958): English rock singer/songwriter and lead singer of Duran Duran. Patron of Humanists UK.[55]
- Dave Leduc (born 1991): Canadian professional fighter and philanthropist. Calls himself an atheist and skeptic, also doesn't believe in an afterlife.
- Geddy Lee (born 1953): Canadian progressive rock musician and lead singer/bassist of Rush.
- Stewart Lee (born 1968): British stand-up comedian, writer and director. Supporter of Humanists UK.[56]
- Yuan T. Lee: American chemist and Nobel laureate in Chemistry. Was one of 22 Nobel Laureates who signed Humanist Manifesto III.[57]
- Robert Lees: Hollywood screenwriter, blacklisted in the 1950s.[58][59]
- John Lennon: British singer-songwriter, producer, and peace activist
- André Michel Lwoff: French microbiologist who won the Nobel Prize in Medicine in 1965 along with François Jacob and Jacques Monod.[60]
- Lovato Lovati: Italian scholar, poet, notary, judge. His works include: Latin verse epistles, and his short commentary of Seneca's tragedies. Witt, Ronald. G. (1994). Latini, Lovato and the Revival of Antiquity. Dante Studies, with the Annual Report of the Dante Society. No. 112. pp. 53–61. P. 58. "Renaissance Grammar." In Renaissance Humanism: Foundations, Forms, and Legacy, edited by Albert Rabil, by W. Keith Percival, 67–85. (Philadelphia: University of Pennsylvania Press, 1988).
Mann, Nicholas. The Origins Of Humanism. In Renaissance Humanism, 1-20. Jill Kraye, 11th ed. (New York: Cambridge University Press, 2011).