Xanthippe Lannister Voorhees is the 15-year-old step-daughter of Jacqueline White and the older half-sister of Buckley Voorhees. Her father is Julian Voorhees.
Xanthippe is extremely spoiled and sarcastic, and her rebellious personality frequently causes conflict with her stepmother and Kimmy. She spends much of the first season trying to figure out the story behind Kimmy's "odd" behavior, in an effort to get her fired.
- Xanthippe's name is pronounced like Zan-thi-pee. She also goes by Xan which sounds like Zan.
- She shares her name with the wife of Socrates and St. Xanthippe of Spain
- The boyfriend Xan makes up to impress her friends was inspired by Thrash from a Babysitters Club book