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. After the war, he attended Yale University, where he engaged in debate and conservative political commentary. Afterward, he worked for two years in the Central Intelligence Agency.

In 1955, he founded National Review, a magazine that stimulated 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.

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, where he became known for his distinctive Transatlantic accent and wide vocabulary.

Buckley's views varied, and are considered less categorically conservative than those of most conservative intellectuals today. His public views on race rapidly changed from the 1950s to the 1960s, from endorsing Southern racism to eagerly anticipating the election of an African American to the presidency.

Buckley called himself both a conservative and a libertarian. He is widely considered one of the most influential figures in the conservative movement.