Ruth Elizabeth Davis, known from early childhood as "Betty", was born on April 5, 1908 in Lowell, Massachusetts, the daughter of Ruth Augusta "Ruthie" (née Favor) and Harlow Morrell Davis, a patent attorney; her sister, Barbara "Bobby", was born October 25, 1909.

The family was Protestant, of English, French, and Welsh ancestry. In 1915, Davis's parents separated and Betty and Bobby attended a Spartan boarding school called Crestalban in Lanesborough, which is located in the Berkshires.

Bette Davis' Family Tree