These are antagonists in The Simpsons, either being villains, or antagonists who are good guys, dependent on the situation.
Antagonists
Those who have had a significant role as an antagonist, are in bold.
- Charles Montgomery Burns: Is the main antagonist of the series, though not appearing in every episode. His significant antagonistic roles include "Marge Gets a Job", "Lady Bouvier's Lover", and "Fraudcast News".
- Sideshow Bob (voiced by Kelsey Grammer): Is the main antagonist of every episode about him.
- Russ Cargill (voiced by Albert Brooks): Is the main antagonist of The Simpsons Movie.
- Cecil Terwilliger: Main antagonist of "Brother from Another Series".
- Jack Lassen: Antagonist of "Blazed and Confused".
- Francine Rhenquist: Antagonist of "Bye Bye Nerdie".
- Krusty the Clown: Although not exactly a villain, Krusty has had an anti-heroic antagonist role in some episodes, name a few.
- Snake Jailbird: Reccuring antagonist in the series.
- Spud and Cooder: Main antagonists of "Bart Carny"
- Francesca Terwilliger: Secondary antagonist of "The Italian Bob"
- Gino Terwilliger: Tertiary antagonist of "The Italian Bob"
- Gary Chalmers: Minor antagonist.
- Artie Ziff (voiced by Jon Lovitz)
- Cesar and Ugolin: In "The Crepes of Wrath"
- Jebediah Springfield: In "Lisa the Iconoclast", he was a murderous pirate named Hans Sprungfeld.
- Lyle Lanley: Main antagonist of "Marge vs. the Monorail".
- Adil Hoxha: In "The Crepes of Wrath".
- Larry Kidkill: In "Eight Misbehavin".
- Moe Szyslak: Minority of being an antagonist.
- Seymour Skinner: Sometimes an antagonist, trying to get Bart back into school.
- Ms. Cantwell:antagonist in "Black Eyes, Please".
- Lt. Smash: in "New Kids on the Blecch".
- Garth Motherloving: In "Sweets and Sour Marge".
- Lionel Hutz: Main antagonist of his last appearance, "Realty Bites".
- Troy McClure: Main antagonist of "A Fish Called Selma".
- Aristotle Amadopolis: Rival of Charles Montgomery Burns, who is also an antagonist.
- Fat Tony: Reccuring antagonist in the series, up until his death.
- Fit Fat Tony: Replaced Fat Tony.
- Herman Hermann: Reccuring antagonist.
- Harper Jambowski: Main antagonist of "Friend with Benefit".
- Simpson family: The protagonists of the series have had a few antagonistic roles.
- Lisa Simpson: in "Little Big Mom", Separate Vocations", "Girly Edition"