Thomas Lanier Williams III, better known by his pen name Tennessee Williams, was an American playwright and screenwriter. He is considered among the three foremost playwrights of 20th-century American drama, alongside Eugene O'Neill and Arthur Miller.

At age 33, after years of obscurity, Williams suddenly became famous with the success of The Glass Menagerie (1944) in New York City. This play introduced "plastic theatre" and closely reflected his own unhappy family background. It was the first of a string of successes, including A Streetcar Named Desire (1947), Cat on a Hot Tin Roof (1955), Sweet Bird of Youth (1959), and The Night of the Iguana (1961). With his later work, Williams attempted a new style that did not appeal as widely to audiences. His drama A Streetcar Named Desire is often numbered on short lists of the finest American plays of the 20th century.

Much of Williams's most acclaimed work has been adapted for the cinema. He also wrote short stories, poetry, essays, and a volume of memoirs. In 1979, four years before his death, Williams was inducted into the American Theater Hall of Fame.