Gretchen Wieners is the daughter of the inventor of Toaster Strudels, which has made her family very rich, and consequently she was spoiled. She is one of the best looking girls in North Shore High School, and her glamorous looks has made her a member of the A-List clique, The Plastics.

Although strinkingly pretty, Gretchen falls beneath Regina George, and keeps being controlled by her like a little doll. Gretchen also has a on-going, off-going relationship with the popular and handsome jock Jason. She can be quite mean if needed, but it seems to be only an influence of Regina, since Gretchen shows to be a lot nicer than Regina, and even quite naive. It is also mentioned that she's Jewish; as she said that her parents got her white-gold hoop earrings for Hanukkah but Regina stole them, so that she could wear them instead.

Throughout the film, Gretchen seems to be treated badly, and belittled by Regina. Althought Gretchen may not like this she knows its better to be in the Plastics hating life then not being in the Plastics at all.

Gretchen can normally be seen wearing a plaid skirt, sweater with heels and a crop top.