Diane Marie Varsi (February 23, 1938 - November 19, 1992) was an American film and television actress.

Born in San Mateo, California, Varsi made her screen debut in Peyton Place (1958), and received a nomination for an Academy Award for Best Supporting Actress. The same year, she shared a Golden Globe as "Most Promising Newcomer" with Sandra Dee and Carolyn Jones. She appeared in the films Ten North Frederick (1958) and Compulsion (1959) and worked steadily throughout the 1960s. Her film career faded by the end of the decade and during the 1970s she played several television roles.

Science fiction and fantasy film fans probably remember Varsi best as Valancy Carmody in The People, a 1972 ABC-TV Movie of the Week based on a story by Zenna Henderson about peaceful alien refugees living on earth. Her portrayal of the would-be Oldest One with a dead-flat affect but compassionate expression and soft, recollected speaking voice was partly caused by the death of her father just before filming began. The director, John Korty , would not let Varsi off for her dad's funeral. Varsi was rendered virtually mute and had to dub in her voice parts later.

Another very brief but memorable Varsi role was Sylvia in I Never Promised You A Rose Garden, based on the Joanne Greenberg novel about a Jewish teen whose allegiance to an alternate universe called the Kingdom Of Yr has led to her being diagnosed as a schizophrenic. In the book, Sylvia was a patient in the mental hospital who ordinarily stood frozen by the wall and very rarely spoke, although completely aware of everything around her. Varsi appears only for a moment in the film and is almost unrecognizable; Deborah, the central character, crumples in misery on the floor of the dayroom, and Varsi breaks away from the wall, kneels by Deborah's side, and whispers a Roman Catholic blessing. It was the last time she was seen on film.

Varsi suffered from Lyme disease, which contributed to her death from respiratory failure.