Janet Garrison (born Herbert Garrison), voiced by Trey Parker, is a recurring character in the South Park cartoon series. For the first eight seasons of the series, the character was known as Mr. Garrison but in season 9 underwent sex reassignment surgery. The character is thereafter known as Mrs. Garrison, despite being unmarried.

Garrison grew up in Arkansas , speaks with a Southern accent, and has a master's degree in mechanical engineering from Denver Community College (as seen in the episode "The Entity").

For the first three seasons, Mr. Garrison was the third-grade teacher at South Park Elementary School, and in constant denial about his blatant homosexuality (insisting that he liked "poontang"). In the fourth season, the status quo was shaken up when he was suspended indefinitely for (inadvertently) trying to solicit sex from Cartman , and afterwards he left the school to publish a sexually explicit romance novel titled In the Valley of Penises (a possible reference to Jean M. Auel's The Valley of Horses, or Jacqueline Susann's Valley of the Dolls, which were equally sexually explicit). He went into hiding after the book was considered the "best homoerotic novel since Huckleberry Finn". After he finally admitted his homosexuality, he tried to re-acquire his job as third-grade teacher but was turned down because the school did not hire gays (although it was likely just a joke because he was hired in the next episode). He was later rehired as the kindergarten teacher, where he enjoyed teaching sex education. By the end of the sixth season he was promoted to the fourth grade after the death of Ms. Choksondik. In contrast to the naive majority of adults in South Park, Mrs. Garrison is one of the show's more cynical characters, as well as being one of the only characters to ever break the fourth wall on the show.