She has black hair. She wears a light orange, long-sleeve shirt, a blue vest, and a dark green skirt. She also has green hair ties, which she uses to put her hair into two puffy pigtails. She is currently the only known student to wear a vest.
Kind, liberal, and defensive, Theresa is insecure about her family's financial situation, and living in a trailer, which she prefers to call a "tiny home." She is sensitive about her family's successes, or rather the lack thereof, and so she makes the claim that her family only downsized to benefit the environment, to hopefully paint a better picture of her unfortunate familial status. She is liberal, and cares a great deal about the environment, acquainting a person's successes with their treatment of the Earth. She is very defensive, and is persistent in her efforts to cover up, or sugarcoat, the things about herself she isn’t proud of.
- This list is incomplete, you can help by
- "The List" - She was shown as a member of the List-making committee.
- "Tonsil Trouble" - Seen in the background on the playground.
- "Super Fun Time" - Seen as Allie Nelson's partner during the field trip.
- "Elementary School Musical" - She was shown singing and dancing.
- "The Ring" - Seen at the Jonas Brothers concert.
- "Ass Burgers" - Cartman sells her a burger.
- "Butterballs" - Seen at the school assembly.
- "Cartman Finds Love"
- "A Scause For Applause" - Seen in the background in the school hallways talking to Kevin Stoley.
- "Let Go, Let Gov" - Seen in the playground.
- "World War Zimmerman"- Seen on the playground turning the jump-rope for Butters.
- "Taming Strange" - Briefly seen in the background in the lunchroom.
- "Gluten Free Ebola" - Seen at the boys' big party, talking to Kelly Pinkerton-Tinfurter.
- "Stunning and Brave"
- "The City Part of Town"
- "You're Not Yelping"- Seen in the hallway.
- "Truth and Advertising"- Seen in the cafeteria.
- "Member Berries"- Seen at the school assembly.
- "Skank Hunt" - Conspires with her fellow female classmates to get back at the boys for Skankhunt42's wrong doings.
- "Wieners Out" - Seen in the stands at the volleyball game.
- "Douche and a Danish" - Seen in the battle between the girls and the boys.
- "Hummels & Heroin" - Rallies with Marcus Preston after witnessing his presentation in the school cafeteria.
- "Doubling Down" - Later takes Heidi out to eat with the other girls. Teases her for her relationship with Cartman, although playfully, she makes very harsh comments and unintentionally hurts Heidi's feelings.
- "Moss Piglets" - Eats with the girls at lunch. Teased by Heidi at the bus stop for living in a trailer park.
- "SUPER HARD PCness" - Seen running to the gym with the students.