Libby Chessler is a major antagonist of the early seasons of Sabrina, the Teenage Witch. She is the popular head-cheerleader at Westbridge High School. She is the high school mean girl.
Libby likes to make fun of people who might be either geeks or outcasts. Libby is a rich spoiled girl who almost everyone at Westbridge High School sees her as a queen. She is the mean girl and queen bee of Westbridge High School. She enjoys giving Sabrina and Jenny a hard time by calling the two "freaks" and called Jenny a "frizzy freak" with her curly hair. Sabrina put a spell on her which she morphed into a pineapple in the pilot episode and is restored back by Aunt Zelda much to Aunt Hilda's disapproval, to which Hilda wanted to chop her up. She is also love rivals with Sabrina, making Libby extremely jealous of her spending time with Harvey Kinkle. She tries but fails to get Harvey's attention. Libby was also transformed into a goat. From season 2-4, she was Mr Kraft right hand person and her spy for Sabrina and her friends. The beginning of season 5 she was shipped off to boarding school.
- Gem Stone from Sabrina the Animated series is similar to her in the animated series. They both rival against each other and Harvey.
- In Sabrina the Teenage Witch movie before the TV series. Katie La More is also similar to Libby. Both of them are rivals and just like Libby she always sees Sabrina as a threat. Unlike the TV series or animated series, she has no interest in Harvey Kinkle. She and Sabrina do rival Seth. But Sabrina turned Seth down and be with Harvey. Katie went back together with Seth.