Judith Guest (born March 29, 1936) is an American novelist and screenwriter. She was born in Detroit, Michigan and is the great-niece of Poet Laureate Edgar Guest (1881–1959).
Guest's first book, Ordinary People, published in 1976, was made into a 1980 film Ordinary People that won the Academy Award for Best Picture. This novel and two others, Second Heaven (1982) and Errands (1997), are about adolescent children forced to deal with a crisis in their family. Guest also wrote the screenplay for the 1987 film Rachel River.
Guest co-authored the mystery Killing Time in St. Cloud (1988) with fellow novelist Rebecca Hill. Guest's most recent book, The Tarnished Eye (2004), is loosely based on a real unsolved crime in her native Michigan.