William Swan Plumer was an American clergyman, theologian and author who was recognized as an intellectual leader of the Presbyterian Church in the 1800s.

William Swan Sonnenschein, known from 1917 as William Swan Stallybrass, was a British publisher, editor and bibliographer. His publishing firm, Swan Sonnenschein, published scholarly works in the fields of philosophy and the social sciences. as well as general literature and periodicals. In 1902 he became the senior managing director of the British publishing firm George Routledge & Sons.

William Thompson Davis (1862–1945) was an American naturalist, entomologist, and historian especially associated with Staten Island in New York City. He was prominent in the borough's affairs throughout his life.

William Tanner Vollmann is an American novelist, journalist, war correspondent, short story writer, and essayist. He won the 2005 National Book Award for Fiction with the novel Europe Central.

William Tallack (1831–1908) was an English prison reformer and writer.

William Chase Taubman is an American political scientist. His biography of Nikita Khrushchev won the Pulitzer Prize for Biography in 2004 and the National Book Critics Circle Award for Biography in 2003.

William Taylor Adams, pseudonym Oliver Optic, was an academic, author, and a member of the Massachusetts House of Representatives.

William Tecumseh Sherman was an American soldier, businessman, educator, and author. He served as a general in the Union Army during the American Civil War (1861–1865), achieving recognition for his command of military strategy as well as criticism for the harshness of the scorched-earth policies that he implemented against the Confederate States. British military theorist and historian B. H. Liddell Hart declared that Sherman was "the most original genius of the American Civil War" and "the first modern general".

William Temple Hornaday, Sc.D. was an American zoologist, conservationist, taxidermist, and author. He served as the first director of the New York Zoological Park, known today as the Bronx Zoo, and he was a pioneer in the early wildlife conservation movement in the United States.

William Tenn was the pseudonym of Philip Klass, a British-born American science fiction author, notable for many stories with satirical elements.