Beatrice Jean "Betty" Hart (née Bryant) is Jenny's mother and the grandmother of Violet. She tends to bicker with her daughter Jenny but still cares for her. She is voiced by Maya Rudolph.
"Miracle on Culpepper Slims Boulevard" shows Betty's middle initial as B. on a piece of mail that she receives.
In the last episode of the show "Betty's Birthday", Betty reveals that her real age is 53. She has gone to huge lengths to conceal her age, including hole punching the date out of her drivers license. Betty tells the family that her mother passes away when she was 53, and that Betty became scared of the same thing happening to her. After seeing how much this meant to her, Jenny, Wayne, and Violet agree to keep her real age a secret.
Betty is a fiery, spunky lady. She tends to have sass in her interactions with everyone around her. Even with these things, she does have a heart for the ones close to her.
However, Betty is shown to have a dark side. When it comes to getting rich, Betty does sleazy and conniving jobs such as slip n falls and abusing a store's return policy. She is also petty and takes vengeance on those who (in her opinion) wronged her, including her own family. Betty is also self-centered and tries to make everything about her, especially at funerals and PTAs.
In "Jenny Unfiltered," her maiden name is rendered as Betty June Bryant, but later her full maiden name was revealed to be Beatrice Jean Bryant in "Mega-Lo-Memories: Part Deux." In "Miracle on Culpepper Slims Boulevard," a letter reads "Ms. Betty B. Hart" which is incorrect as she uses Hart as her married name and her middle name is either July or June.