Cuoco was born in Camarillo, California, the elder daughter of Layne Ann (née Wingate), a homemaker, and Gary Carmine Cuoco, a realtor. Her father is of Italian descent, and her mother has English and German ancestry. As a child, Cuoco was once a nationally-ranked amateur tennis player, a sport she took up when she was three years old. She stopped playing in 2002 at the age of 16.