Lettice was the daughter of sir Thomas Penyston and Alice Bulstrode. The date and place of her birth have not been found.
She had three marriages/partners. Her first husband was Robert Knollys. They were married, but the date and place have not been found. Their four known children were sir Francis (c1514-1596), Joan (c1516-?), Elizabeth (?-?) and Margaret (c1502-?).
Her second husband was sir Robert Lee. They were married, but the date and place have not been found. They had no known children.
Her third husband was sir Thomas Tresham. They were married, but the date and place have not been found. They had no known children.