William Frank Buckley Jr. (born William Francis Buckley; November 24, 1925 – February 27, 2008) was an American conservative writer, public intellectual, and political commentator.

Born in New York City, Buckley spoke Spanish as his first language before learning French and then English as a child. He served stateside in the United States Army during World War II. Following the war, he attended Yale University, where he engaged in debate and conservative political commentary; he graduated from Yale with honors in 1950. Afterward, he worked at the Central Intelligence Agency for two years.

In 1955, Buckley founded National Review, a magazine that stimulated the growth and development of the conservative movement in the United States. In addition to editorials in National Review, Buckley wrote God and Man at Yale (1951) and more than 50 other books on diverse topics, including writing, speaking, history, politics, and sailing. His works include a series of novels featuring fictitious CIA officer Blackford Oakes and a nationally syndicated newspaper column. Buckley ran unsuccessfully for mayor of New York City in 1965 on the Conservative Party line. From 1966 to 1999, Buckley hosted 1,429 episodes of the public affairs television show Firing Line, the longest-running public affairs show with a single host in American television history; through his work on the show, he became known for his distinctive Transatlantic accent and wide vocabulary.

Buckley is widely considered to have been one of the most influential figures in the conservative movement in the United States.