Emily Marx is a student at South Park Elementary. She first appear at Heidi Turner's slumber party in "Marjorine", and later at the Jonas Brothers concert in "The Ring". Her name was confirmed in "Bass to Mouth".
Emily has light blonde hair and wears a dark blue jacket and light green pants. In earlier appearances, she wore a navy blue jacket with blue-grey trousers. In "Marjorine", she wears a turquoise pajama top with green and orange hearts, and green pants.
She seems to be relatively sensitive to social criticism, considering in "Bass to Mouth" she was embarrassed, not because her mother was in rehab, but because the other girls might find out.
It was shown in "Bass to Mouth" that her and Tammy are very close friends, probably best friends, considering they both admitted and comforted each other over their mothers being addicts/alcoholics, a very personal matter. They are also seen sitting together in the school gymnasium in "Cock Magic". At the Board Girls club, they are playing a marvel game together.
- "Marjorine" - Seen at Heidi Turner's slumber party.
- "The List" - Appears as part of the girls' list-making committee.
- "Tonsil Trouble" - Can be seen in the background.
- "Super Fun Time" - Seen as Nelly's partner during the field trip. Held hostage along with the rest of the class.
- "The Ring" - Appeared at the Jonas Brothers concert.
- "Bass to Mouth" - Her first name, as well as the fact that her mother is in rehab for alcoholism, was revealed in a conversation with Tammy Nelson.
- "The Poor Kid" - Appears in the hallways at South Park Elementary as well as in the crowd of onlookers watching Kenny's parents being arrested.
- "Butterballs" - Seen in Stan's anti-bullying video and at the school assembly.
- "Let Go, Let Gov" - Seen in the school hallways talking to Nelly and Tammy Nelson.
- "Informative Murder Porn" - Seen in Park County Community Center.
- "The Cissy" - Seen in the hallway with Jenny Simons.
- "Cock Magic"- Seen at the volleyball game sitting in the bleachers next to Tammy Nelson.
- "Safe Space" - Seen at Whole Foods.
- "Skank Hunt" - Seen in the hallway.
- "Wieners Out" - Seen in the stands at the volleyball game.
- "Douche and a Danish" - Seen in the battle between the girls and the boys.
- "Not Funny" - Seen at church.
- "Moss Piglets" - Seen in the school hallway.
- "A Boy And A Priest" - Seen at church.
- "The Problem with a Poo" - Seen at Mr. Hankey's Christmas Concert.
- "Board Girls" - Seen in the Board Girls Gaming Club.
- "Christmas Snow" - Seen at the Christmas Festival.
- ""South Park" Bass to Mouth (TV episode 2011)". IMDb.com.