Streep's father Harry was of German and Swiss ancestry. Her mother had English, German, and Irish ancestry.
Mary Louise Streep was born on June 22, 1949, in Summit, New Jersey. She is the daughter of Mary Wilkinson Streep (née Mary Wolf Wilkinson), a commercial artist and art editor; and Harry William Streep, Jr., a pharmaceutical executive. She has two younger brothers, Dana David and Harry William III.
Streep's mother, whom she has compared in both appearance and manner to Dame Judi Dench, strongly encouraged her daughter, and instilled confidence in her from a very young age. Although Streep was naturally more introverted than her mother, at times, when she later needed an injection of confidence in adulthood, she would consult her mother, asking her for advice.