Kaley Christine Cuoco (born November 30, 1985) (pronounced /ˈkeɪliː ˈkoʊkoʊ/) is an American television actress, best known for her roles as Bridget Hennessy on the sitcom 8 Simple Rules, Billie Jenkins on the supernatural drama series Charmed, and Penny on the CBS sitcom The Big Bang Theory.

Cuoco was born in Camarillo, California, to Gary Carmine Cuoco, an Oxnard, California realtor, and Layne Ann Wingate, a homemaker. She has a younger sister, Briana. Kaley was schooled on the set and earned her high school diploma at the age of 16. She had many pets, including a Jack Russell Terrier named Raquel.

Cuoco began modeling and acting at age 6. Her first major role was in the 1992 TV movie Quicksand: No Escape. Her role as Maureen McCormick in the 2000 TV movie Growing Up Brady brought her much attention, as well as a role on the CBS sitcom Ladies Man. In 2004, in addition to her role on 8 Simple Rules where she played a teenager, she has had starring roles on the NBC miniseries 10.5, on the ABC Family original movie Crimes of Fashion, and in the independent film Debating Robert Lee. In 2000 she starred in the Disney Channel Original Movie Alley Cats Strike.