Penelope Lang (Catherine Disher) is Betty's self-obsessed, heartless rival on Earth, who thinks of herself as the most popular girl at her school. Her favorite pasttime is ridiculing the other students, Betty and Noah in particular. She is rich, spoiled, and often uses her popularity or wealth to undermine Betty's social standing, a plan that inevitably goes wrong and violently backfires on Penelope every time. She is usually seen with two sidekicks named Megan and Sarah. She’s used to getting her own way — even if it means stepping all over other people. In fact, she enjoys getting her own way more if she has to step over other people to do so. In "Bracelet Yourself", she tampered with Betty's bracelet which is property of the Galactic Guardians and caused the Starcruiser to lose control. She also seems to not hate, but despise Betty enough to be violent, for in "Pre-Teen Queen of Outerspace", she attempts to kill Betty and her friends, though she thinks it is just a dream. Being Betty's rival, she also dislikes Noah just about as much as she dislikes Betty. Though she has come close to discovering the existence of the Galactic Guardians, having stolen Betty's bracelet in "Bracelet Yourself" and even having tampered with and in Power of the Pharaoh, read out of Betty's own "captain's log" (this causes people to think that Betty is a science fiction author), she quickly dismisses all of the evidence. She doesn't believe the evidence are real.
- Queen Penelobee - clone
- Megan - minion
- Sarah - minion
- Poopsie - pet cat
- Mr. Lang - father
- Mrs. Lang - mother
- Catherine Disher, the voice of Penelope, is better known as the voice of Jean Grey on X-Men: the Animated Series, as well as coroner Natalie Lambert on the live action horror-crime drama series Forever Knight. She also appeared in the long-forgotten 1986 sci-fi film, The Vindicator, where she played a scientist who gets killed by a rage-filed chimpanzee.
- In Pre-Teen Queen of Outer Space, the Bee People consider Penelope to be the most despicable female in the universe. Although, she might have a sensitive side. In The Market, she is seen crying because her cat Poopsie died.