I forgot to mention, I'm planning to blow up the dam with you inside.
~ Cecil to Bob, Bart and Lisa

Cecil Terwilliger is a recurring antagonist of The Simpsons. He is the main antagonist of the 1997 episode Brother from Another Series and the secondary antagonist of the 2007 episode Funeral for a Fiend. He is the younger brother of Sideshow Bob, and son of Robert Terwilliger Sr. and Dame Judith Underdunk. He also has his sister-in-law named Francesca Terwilliger and his nephew named Gino Terwilliger.

He was voiced by David Hyde Pierce.


Cecil felt deeply jealous of his older brother Bob, because as children, Cecil was ignored repeatedly by his parents, and instead compared to Bob. As adults, Bob and Cecil didn't talk to each other for years, because Cecil wasn't chosen for Krusty's show during the sideshow auditions. Krusty, Cecil's childhood hero, considered Cecil too unfunny, as soon as he noticed Bob, he chose him as his new sidekick. (Ironically, despite being Cecil being jealous of Bob for getting the part instead of him, Bob later decided to frame Krusty so he could create his own show).

As his introduction story progresses, we discover that he has also hidden criminal behaviors, which have somehow rooted from his jealousy against his brother after what happened in the auditions. As the episode progresses on, Bart and Lisa learns of an embezzlement scheme that will endanger the local hydroelectric dam that is funded for it, and initially believed that Bob was the one who embezzled it, but Cecil reveals himself to be the true culprit as he is holding Bob, Bart, and Lisa hostage with a gun. It was then he revealed his true colors to frame Bob for the embezzlement scheme and blow the dam with him, Bart, and Lisa inside to get revenge for the audition incident walk away clean with the money.

Fortunately, Bob, Bart, and Lisa went on to work together to stop Cecil in his tracks and turned him over to the police, but unfortunately, Chief Wiggum arrests Bob as well, believing him to be involved. As both brothers are taken away, Cecil tricks Bob into swearing revenge on Bart for not defending his innocence, and as Bob fell for it, he realized he just made Bart his enemy again, and angrily holds Cecil responsible for it.

When Bob was later arrested for attempting to kill the Simpsons again, Cecil helped him to avoid the prison and lure Bart into the trap. After Bob's fake funeral, Cecil came to unhappy Bart who felt guilty for Bob's death and suggested him to make his peace with Bob before his cremation. This led Bart to visit to the funeral house, only to be locked in the coffin by Bob who then tried to burn him up.

Currently, Cecil is remaining in prison, along with Bob, Francesca, Gino, as well as their parents.


  • As a homage to the television series Fraiser, Cecil is based on David Hyde Pierce's character Niles (brother of Kelsey Grammer's Fraiser Crane).
  • Cecil could easily be the evilest villain of the series as he tried to flood the city and kill his brother and two children (Bart and Lisa). However, he is outranked by Russ Cargill, who is more dangerous and ruthless than Cecil.


          The Simpsons Villains

Springfield Republican Party
Birch Barlow | Blue-Haired Lawyer | Lindsey Naegle | Mr. Burns | Waylon Smithers

Terwilliger Family
Cecil Terwilliger | Dame Judith Underdunk | Francesca Terwilliger | Gino Terwilliger | Robert Terwilliger Jr. | Robert Terwilliger Sr.

Springfield Mafia
Fat Tony | Fit Tony

Environmental Protection Agency
Russ Cargill

Recurring Characters
Agnes Skinner | Artie Ziff | Baby Gerald | Constance Harm | Dolph Starbeam | God | Jebidiah Springfield | Herman Hermann | Itchy | Jessica Lovejoy | Jimbo Jones | Kearney Zzyzwicz | Matt Groening | Nelson Muntz | Patty and Selma Bouvier | Senator Mendoza | Snake Jailbird | Space Mutants | Wainwright Montgomery Burns

Treehouse of Horror
Bart (Fly) | Billy the Kid | Count Burns | Gremlin | Groundskeeper Willie | Homer's Clones | Hugo Simpson II | Jonathan Frink Sr. | Kang and Kodos | Killer Krusty Doll | Killer Toupée | King Snorky | Lard Lad | Muttonchop Murderer | Ned Flanders | Seymour Skinner | The Blob | The Collector | The Devil | The Grand Pumpkin | Witch Marge

Guest Star Characters
Adil Hoxha | Adolf Hitler | Andy Hamilton | Bart Simpson's Creatures | Blue-Eyed Man | Bob Arnold | Captain Mordecai Barrows | Cesar & Ugolín | Clownface | Cooder | Comic Book Guy (Brick Like Me) | Devan & Quenley Woosterfield | Dexter Colt | Dwight Diddlehopper | Francine Rhenquist | Frank Grimes, Jr. | French Chef | Hank Scorpio | Howard K. Duff VIII | Ironfist Burns | Jack Crowley | Jim Hope | Julia | Kindergarten Teacher | Larry Kidkill | Lucille Botzcowski | Lyle Lanley | Mav & Portia | Miss Goodthighs | Molloy | Movementarians | Mr. Dirt | Nigel Bakerbutcher | Officer Krackney | Professor Werner Von Brawn | Rex Banner | Robotic Richard Simmons | Shadow Knight | Simon Cowell | Spud | Stanley DeGroot | Stubborn Ape | The Leader | White Dog | Will Wright