Jillian Dion is an American costume designer, primarily known for her work on the hit series *Stranger Things*, for which she has served as the costume designer since its third season. Her career includes notable collaborations with producer Ryan Murphy on productions such as *American Horror Story*, *The Prom*, and *The Politician*. Her costumes are praised for their ability to evoke specific eras with historical accuracy, particularly the 1980s, and to visually define the characters' identities and evolution. Her work has earned her numerous accolades, including a Primetime Emmy Award and a Costume Designers Guild Award, solidifying her reputation as one of the leading figures in contemporary costume design.