Stanley "Stan" Marsh is a fictional character in the adult animated television series South Park. He is voiced by and loosely based on series co-creator Trey Parker. Stan is one of the series' four central characters, along with Kyle Broflovski, Eric Cartman, and Kenny McCormick. He debuted on television when South Park first aired on August 13, 1997, after having first appeared in The Spirit of Christmas shorts created by Parker and long-time collaborator Matt Stone in 1992 and 1995.

South Park: Bigger, Longer & Uncut is a 1999 American adult animated musical comedy film based on the animated sitcom South Park. The film was directed by series creator Trey Parker from a screenplay co-written with series co-creator Matt Stone and Pam Brady; and stars Parker, Stone, Mary Kay Bergman, and Isaac Hayes, all of whom reprise their roles from the series, with George Clooney, Eric Idle, and Mike Judge in supporting roles. The plot follows Stan, Kyle, Cartman, and Kenny as they sneak into an R-rated film starring the Canadian comedy duo Terrance and Phillip, after which they begin swearing. When the consequent moral panic culminates in the United States declaring war on Canada, Stan, Kyle and Cartman take it upon themselves to save Terrance and Phillip from execution, while Kenny tries to prevent a prophecy involving Satan and Saddam Hussein's intent to conquer the world.