Born in Altadena, California, Van Houten was the middle child of three girls. Her mother, Diane, was a homemaker, and her father, Paul, was an engineer. Van Houten was a straight-A student and popular in her high school, but she began experimenting with drugs after her parents' divorce when she was 16.
In August 1969, at the age of 19, Van Houten followed Charles Manson's instructions and participated in the murders of Leno and Rosemary LaBianca, which were carried out the day after the Tate murders. She stabbed Rosemary LaBianca 14 times in the back with a knife.
Van Houten was arrested in November 1969 and charged with two counts of first-degree murder. She was convicted in 1971 and sentenced to life in prison.
In 2016, Van Houten was recommended for parole for the 19th time, but her parole was denied. She will be eligible for parole again in 2027.