Jimmy Neutron
The Adventures of Jimmy Neutron character
Jimmy Neutron
Full name: James Issac Neutron
Species: Human
Aliases: Nerdtron
Hugh & Judy Neutron (parents)
Granny Neutron
Baby Eddie (cousin)
Invisible Hamsters
Darwin the Goldfish
Carl Wheezer
Sheen Estevez
Jet Fusion
Timmy Turner
Cosmo & Wanda
Danny Fenton
SpongeBob SquarePants
Cindy Vortex (unofficial girlfriend)
King Goobot & The Yolkians
Professor Finbarr Calamitous & Beautiful Gorgeous
Denzel Q. Crocker
Jimmy Negatron
Baby Eddie
Eustace Stritch
Grandma Taters
The Junkman
First appearance:
Runaway Rocketboy!
Voiced by: Debi Derryberry

James Isaac "Jimmy" Neutron is the main protagonist of The Adventures of Jimmy Neutron: Boy Genius. He is the world's smartest 10-year-old. He is named after scientists Sir. James Isaac Newton, and James Chadwick who was nicknamed "Jimmy Neutron", because of his discovery of the neutron.

Jimmy is a genius inventor, but his inventions seem to cause more destruction than anything and it is usually up to him to stop them. He lives in Retroville with his robot dog, Goddard, who is named after Robert H. Goddard (a pioneer in modern rocketry) and his parents, Hugh and Judy Neutron.


Jimmy has a disproportionately large head (which needs to house his large brain), blue eyes, and brown ice cream-shaped hair. He is often teased because he is shorter than most boys of his age. Jimmy's wardrobe consists almost exclusively of red T-shirts that sport his trademark symbol of electrons, circling a nucleus. He also wears blue jeans and a pair of black and white Converse Chuck Taylor All-Stars. His underwear consists of plaid boxer shorts as shown in the movie and in the first episode of the series, He wears knee socks. In the movie, Jimmy wore blue shorts and brown shoes. He also wears his blue lab coat (and sometimes his welding mask)


Jimmy is a genius having an I.Q. of 210. In a number of episodes his classmates are annoyed and angered because Jimmys brilliance renders trying to win projects and competitions things pointless (in fact Jimmy has been banned for life from the science fair to give normal kids an actual chance). This brain, a source of constant comment, allows him to invent devices that accomplish even the impossible. That might seem like a gift to most people, but to Jimmy Neutron, it often causes him trouble. He designs his wild inventions to help him deal with bothersome chores, however the inventions tend to have a flaw (usually caused by an obvious oversight) which result in a catastrophe which only he can solve. He's rarely ever thanked however as people usually know he's the cause of the problem in the first place.

In the moment of crisis, he will urge his brain by saying, "Think, think, think!", where upon viewer enters Jimmy's ear and goes into his brain to observe its inner workings as well, as to relive a scene from the early part of the episode. Jimmy will then shout, "Brain Blast!", and arrive at the solution for whatever danger he has landed himself, his friends, or his town in. But in the 3rd season, he seems to stop Brain Blasting and comes up with ideas right away, with the exception being Fundemonium.

Jimmy has a sweet personality, although sometimes he can be a bit arrogant. Jimmy is shown to be quite irritable around most people, the exception being his friends. He can be friendly at times, that he needs (or wants to be), but can come off as a smart alec or nerd occasionally. He enjoys playing the hero, often taking a staunch stand against anyone he believes to be evil. He won’t back down from his beliefs as he strongly believes in himself. Jimmy is quite charming when he least tries to be, such as at the party, that he throws at his parents' absence in an early episode. He cares for his friends, family and Retroville.


However, he does have a few weaknesses; one of them is his poor communication skills. It takes him hours to explain things the “Science way” and people find his explanations hard to understand and would ask for a shorter version of his story instead. Cindy Vortex calls him silver-tongued (in a sarcastic way), in the episode “Love Potion #976/J” as he finds it, which is accessible to him only, by means of a DNA scan.



The llama-obsessed Carl Wheezer and UltraLord-obsessed Sheen Estevez are Jimmy’s best friends. They may not be as smart as Jimmy, but they are very loyal to him. They are willing to help Jimmy as much as possible. Normally, these two unlikely heroes play the foils to Jimmy's genius, and sometimes solve the episode's crisis with some innocent or insane observation. Other times, they merely cause the problem. They accompany him in his wild adventures and end up in trouble.

Jimmy’s friends also includes Libby Folfax and Cindy Vortex. They constantly tease Jimmy for having a large head and for getting himself and the town into trouble. However, these girls get to join in Jimmy’s adventures and help him save the day.

Cindy and Jimmy constantly fight with one another, and consider themselves as “rivals”. But eventually, they grow to love each other, leading to a love/hate relationship. In due course, it seems that they fight to hide their true feelings. It is hard to say who really motivates the relationship, but from what we can see, it is Cindy who gives it a little push and Jimmy is quick to respond to these hints of affection. Their relationship develops further in season 3, and in the final episode “Lady Sings the News,” Jimmy finally kisses Cindy.



  • "Gotta blast!"
  • "Brain blast!"
  • "I already told you Goddard, this invention helps me bring down my ego when Cindy calls me a 'know-it-all'. Which is pretty hard to do when you actually do know it ALL." -Substitute Creature
  • "Twenty-five cents?! I'm worth at LEAST-" -Birth of a Salesman
  • "Hmm... This candy is so strong it seems to have developed a psychological need in people. Let the exploitation begin!!" -Krunch Time
  • "to the hovercar?" -Stranded
  • I accept your nomination as mayor of Donkey Town." -Stranded
  • "I'm sorry, miss. Do I know you?" -Normal Boy
  • "Ha! Just kidding! Let's PARTY!!!" -The Egg-Pire Strikes Back
  • "No, but we survived by learning to help each other, & that's what makes us rich: rich in friendship!" -A Beautiful Mine
  • "(Goddard shows on screen)...Go back in time and tell Cindy you will lose the contest.' Jimmy: Goddard, whose side are you ON?!!..." -Birth of a Salesman
  • "This is going to be a memorable Halloween Goddard. That is if we survive." - Nightmare in Retroville
  • "That's a nice story, girls, but as it stands, I'M WINNING THIS CONTEST!!!" - Birth of a Salesman
  • (Jimmy talking to Cindy) "I can't talk, I can't think. Everywhere I go, you're there!" Cindy: "What kind of sick joke is this?" Jimmy: "Oh, you're gonna make me say it, aren't you? Alright then, I'll say it.....I love you Cindy Vortex! "- Love Potion #976/J