Jennifer's grandma was one of the grandparents of Jennifer Parker.
Jennifer told her boyfriend Marty McFly that she would be at her grandma's house on the evening of October 25, 1985, and so wrote down her grandma's telephone number, 555-4823, along with I love you!, on the back of a "Save the Clock Tower" flyer given to Marty by the Clock Tower Lady. Although Marty promised to call Jennifer there, he never got around to doing so.
Whether Jennifer's grandma was her maternal or paternal grandparent remains unrecorded.
Behind the scenes
- In George Gipe's novelization, Jennifer's grandma's telephone number is given as “243-8480” (page 22).