Sylvanus Griswold Morley was an American archaeologist and epigrapher who studied the pre-Columbian Maya civilization in the early 20th century. Morley led extensive excavations of the Maya site of Chichen Itza on behalf of the Carnegie Institution and published several large compilations and treatises on Maya hieroglyphic writing. He also wrote popular accounts on the Maya for a general audience.

Sylvanus Stall was a United States Lutheran pastor, most famous for his 1897 sex education and anti-masturbation book What A Young Boy Ought To Know and its many sequels.

Sylvester Bliss (1814–1863) was a Millerite minister; editor and author.

Sylvester Mowry was an American politician, miner, and land speculator. He is best remembered as an early advocate for establishing the Arizona Territory. He was also a West Point graduate and officer of the United States Army who was later arrested as a traitor during the American Civil War.

Sylvia Nora Townsend Warner was an English novelist, poet and musicologist, known for works such as Lolly Willowes, The Corner That Held Them, and Kingdoms of Elfin.