William Cuthbert Faulkner (/ˈfɔːknər/; September 25, 1897 – July 6, 1962) was an American writer. He is best known for his novels and short stories set in the fictional Yoknapatawpha County, Mississippi, a stand-in for Lafayette County where he spent most of his life. A Nobel laureate, Faulkner is one of the most celebrated writers of American literature, often considered the greatest writer of Southern literature and regarded as one of the most influential and important writers of the 20th century.

Faulkner was born in New Albany, Mississippi, and raised in Oxford, Mississippi. During World War I, he joined the Royal Canadian Air Force, but did not serve in combat. Returning to Oxford, he attended the University of Mississippi for three semesters before dropping out. He moved to New Orleans, where he wrote his first novel Soldiers' Pay (1925). He went back to Oxford and wrote Sartoris (1927), his first work set in Yoknapatawpha County. In 1929, he published The Sound and the Fury. The following year, he wrote As I Lay Dying. Later that decade, he wrote Light in August; Absalom, Absalom!; and The Wild Palms. He also worked as a screenwriter, contributing to Howard Hawks's To Have and Have Not and The Big Sleep, adapted from Raymond Chandler's novel. The former film, adapted from Ernest Hemingway's novel, is the only film with contributions by two Nobel laureates.

Faulkner's reputation grew following publication of Malcolm Cowley's The Portable Faulkner, and he was awarded the 1949 Nobel Prize in Literature for "his powerful and unique contribution to the modern American novel." He is the only Mississippi-born Nobel laureate. Two of his works, A Fable (1954) and The Reivers (1962), won the Pulitzer Prize for Fiction. Faulkner died from a heart attack on July 6, 1962, following a fall from his horse the month before. Ralph Ellison called him "the greatest artist the South has produced".

Faulkner was born on September 25, 1897, in New Albany, Mississippi, the first of four sons of Murry Cuthbert Falkner and Maud Butler. His family was upper middle-class, but "not quite of the old feudal cotton aristocracy". After Maud rejected Murry's plan to become a rancher in Texas, the family moved to Oxford, Mississippi in 1902, where Faulkner's father established a livery stable and hardware store before becoming the University of Mississippi's business manager. Except for short periods elsewhere, Faulkner lived in Oxford for the rest of his life.

Faulkner spent his boyhood listening to stories told to him by his elders – stories that spanned the Civil War, slavery, the Ku Klux Klan, and the Faulkner family. Young William was greatly influenced by the history of his family and the region in which he lived. Mississippi marked his sense of humor, his sense of the tragic position of "black and white" Americans, his characterization of Southern characters, and his timeless themes, including fiercely intelligent people who are dwelling behind the façades of good ol' boys and simpletons. He was particularly influenced by stories of his great-grandfather William Clark Falkner, who had become a near legendary figure in North Mississippi. Born into poverty, the elder Falkner was a strict disciplinarian and was a Confederate colonel. Tried and acquitted twice on charges of murder, he became a member of the Mississippi House and became a part-owner of a railroad before being murdered by a co-owner. Faulkner incorporated many aspects of his great-grandfather's biography into his later works.

Faulkner initially excelled in school and skipped the second grade. However, beginning somewhere in the fourth and fifth grades, he became a quieter and more withdrawn child. He occasionally played truant and became indifferent about schoolwork. Instead, he took an interest in studying the history of Mississippi. The decline of his performance in school continued, and Faulkner wound up repeating the eleventh and twelfth grades, never graduating from high school. As a teenager in Oxford, Faulkner dated Estelle Oldham (1897–1972), the popular daughter of Major Lemuel and Lida Oldham, and he also believed he would marry her. However, Estelle dated other boys during their romance, and, in 1918, Cornell Franklin (five years Faulkner's senior) proposed marriage to her before Faulkner did. She accepted.

When he was 17, Faulkner met Phil Stone, who became an important early influence on his writing. Stone was four years his senior and came from one of Oxford's older families; he was passionate about literature and had bachelor's degrees from Yale and the University of Mississippi. Stone read and was impressed by some of Faulkner's early poetry, becoming one of the first to recognize and encourage Faulkner's talent. Stone mentored the young Faulkner, introducing him to the works of writers like James Joyce, who influenced Faulkner's own writing. In his early 20s, Faulkner gave poems and short stories he had written to Stone in hopes of their being published. Stone sent these to publishers, but they were uniformly rejected. In spring 1918, Faulkner traveled to live with Stone at Yale, his first trip to the North. Through Stone, Faulkner met writers like Sherwood Anderson, Robert Frost, and Ezra Pound.

During the First World War, Faulkner attempted to join the US Army. There are accounts of this that indicate he was rejected for being under weight and his short stature of 5'5". Other accounts purport to prove that the aforementioned accounts are false. Although he initially planned to join the British Army in hopes of being commissioned as an officer, Faulkner instead joined the Royal Air Force (Canada) with a forged letter of reference and left Yale to receive training in Toronto. He enlisted in Toronto on July 10, 1918, as a Private (II Class), No.173799, in the RAF (C) but never saw active service overseas during the First World War, only training at the recruit depot in Toronto.