Christopher Haden-Guest, 5th Baron Haden-Guest (born February 5, 1948), better known as Christopher Guest, is an American screenwriter, composer, musician, director, actor and comedian. He is most widely known in Hollywood for having written, directed and starred in several "mockumentary" films that feature a repertory-like ensemble cast. In the United Kingdom, he holds a Baronial peerage, and has publicly expressed a desire to see the House of Lords reformed as a democratically-elected chamber. Despite initial activity in the Lords, his career there was cut short by the House of Lords Act 1999.

Guest was born in New York City, the son of Peter Haden-Guest, a British United Nations diplomat who later became 4th Baron Haden-Guest, and his second wife, Jean Pauline Hindes, a former vice president of casting at CBS. Guest's maternal grandparents were Jewish immigrants from Russia, while a paternal great-grandfather was Colonel Albert Goldsmid, a British Jew who founded the Jewish Lads' and Girls' Brigade. Although both of Guest's parents were born Jewish, they became atheists and Guest had no religious upbringing.

Guest spent parts of his childhood in his father's native UK. Guest attended The High School of Music & Art (New York City), studying classical music (clarinet). He later took up the mandolin and became interested in country music. He also played guitar with Arlo Guthrie, who went to the same school. Guest later began performing with bluegrass bands until he took up rock and roll.