Elizabeth Montgomery was born on April 15, 1933, in Los Angeles, California, the daughter of actor Robert Montgomery and his wife, Broadway actress Elizabeth Bryan Montgomery (née Allen).

She had an older sister, Martha Bryan Montgomery, who died as an infant (named after her aunt Martha-Bryan Allen) and a brother, Robert Montgomery, Jr. (1936 - 2000). She attended Westlake School for Girls (now Harvard-Westlake School in Holmby Hills). After graduating from Spence School, she attended the American Academy of Dramatic Arts for three years.

Elizabeth Montgomery's Family Tree