Rachel Sarah Bilson (born November 13, 1981) is an American actress. She is best known as Summer Roberts on The O.C., an American television "dramedy", which focuses on the lives of the beautiful and wealthy in a gated Newport Beach community.

Bilson was born in Los Angeles, California, and is the daughter of writer/director Danny Bilson and granddaughter of director Bruce Bilson. Her stepmother is Heather Medway, an actress and the mother of Bilson's two-year-old half-sister Hattie.