Leopold "Butters" Stotch, voiced by Matt Stone, is a fictional character in the animated TV series South Park. His nickname is a play on the word butterscotch.

Butters has been in the show since the beginning, though initally only as a background character. He was later adopted by Stan, Kyle and Cartman as their fourth friend when Kenny died (semi-)permanently. Later, Kyle, Stan and Cartman decided that they didn't like Butters very much and chose Tweek to "fill the void" instead.

Butters, as a character, is much nicer, more innocent and more gullible than the four main characters. He has a bit of a stutter and a southern accent. His parents, Chris and Lynda Stotch are strict and over-protective, though Lynda once tried to kill him.

Butters was often referred to as "a little pussy" and the boys got him to do anything for them—often getting Butters grounded in the process. The boys made him go on the Maury Povich show with fake testicles attached to his chin.

Butters was the first to mature and give a "semen sample."

Butters' alter ego is Professor Chaos, a supervillain or mad scientist he became when the boys dumped him. He spreads chaos with his sidekick and his minions (his pet hamsters).

Early in his career as Professor Chaos, Butters was successful at bringing chaos to his fourth grade classroom when he stole the erasers from the chalkboard. During the process of changing into his Professor Chaos costume Butters was discovered by Dougie, who chose to join him as his sidekick, General Disarray, after being eliminated in the boys' quest to find a new fourth member. Together, Professor Chaos and General Disarray hatched out evil plots that included trying to flood the world with his garden hose and destroying the ozone layer with aerosol spray.

In episode #607, "Simpsons Already Did It," Butters devises a series of supposedly original evil plots, only to abandon each of them after General Disarray informs him that they have already been used on The Simpsons. He is later consoled by the reassurance this is only because the show has run so long, not his own lack of creativity.

In the episode "Good Times with Weapons," Stan, Kyle, Cartman, and Kenny acquire ninja weapons at a fair. They are then turned into anime-style ninjas. Butters wants to play with them, but they disallow him. Butters then becomes Professor Chaos and has a "ninja fight" with the gang. Kenny throws a ninja star into Butters' eye.

Butters has a tuft of yellow hair, and wears a light blue jacket with green pants. His birthday is on September 11. He is loosely based on South Park director of animation Eric Stough.

Butters was previously a tap dancing champion, but quit after his dancing caused a freak accident resulting in the death of 8 audience members.