Christopher Guest (born February 5, 1948, New York, New York) is a British-American actor, writer, director, composer, and musician.

He is best known for his portrayal of Nigel Tufnel in the mockumentary movie This is Spinal Tap, and his time as a cast member on NBC's Saturday Night Live (1984-1985). Guest made his first appearance as Tufnel on the 1980 album Lenny and the Squigtones by "Lenny and Squiggy"' (comedians Michael McKean and David Lander).

He went on to write, act in, and direct several other heavily improvised mockumentaries: He married Jamie Lee Curtis in 1984. They have two children: Anne (born 1986) and Thomas (born March 1996 ).

Guest became the fifth Baron Haden-Guest of Saling (near Braintree), when his father died in 1996.