Blake Lively was born in Tarzana, Los Angeles to actors Ernie and Elaine Lively. She was raised as a Southern Baptist. The youngest of five siblings, Blake Lively has a brother, Eric, two half-sisters, Lori and Robyn, and a half-brother, Jason. Both of her parents and all of her siblings are, or have been, in the entertainment industry. During Blake Lively's childhood, her parents would take her with them to acting classes that they taught because they did not want to leave her with a babysitter. Blake Lively said that watching her parents teach acting classes helped her learn the "drills" of acting and gain confidence as she got older. Blake Lively stated that as a child, her mother would bring her to Disneyland twice a week as an opportunity "to have some extra time to bond"; Blake Lively has stated, due to all the time she spent there, she felt that she "grew up at Disneyland."
Blake Lively was not at all interested in acting, but during the summer between her junior and senior years, her brother, Eric, made his agent send her out on a few auditions over a period of a few months; of the few auditions, she got the role of Bridget for The Sisterhood of the Traveling Pants. Blake Lively filmed her scenes in The Sisterhood of the Traveling Pants between her junior and senior years at Burbank High.