Which South Park episode is a musical about the Mormon religion?

The South Park episode that is a musical about the Mormon religion is “All About Mormons.” It follows Stan Marsh after a Mormon family moves to South Park and their son Gary quickly impresses the other children with his unusual politeness, talent, and confidence.

The episode is the twelfth installment of South Park’s seventh season and first aired on November 19, 2003. Its story includes musical flashbacks about Joseph Smith, the founding of Mormonism, and the origin of the Book of Mormon. The songs parody the upbeat style of traditional musical theater while presenting the Mormons as unusually wholesome and successful.

The episode drew on Trey Parker and Matt Stone’s experiences growing up in Colorado and knowing Mormon classmates. Its themes later influenced The Book of Mormon, the Broadway musical Parker and Stone created with Robert Lopez, which opened in 2011. A common mix-up is confusing the episode with that later stage musical: The Book of Mormon is a separate production, while “All About Mormons” is the South Park episode.