Dexter's Laboratory Wiki
“No, Dee Dee, no!”
Aliases Boy Genius, Dexstar, Little Brother, Dorkster, Dex, D, Dextor, Dex-Bot, The Great and Powerful Dexter, Number 12, Action Dexter, Old Man Dexter
Gender Male
Species Human
Family Dee Dee (sister)
Mom (mother)
Dad (father)
Grandpa (grandfather)
Fergle O'Reilly (uncle)
Dextamina (great aunt)
Occupation Student, Scientist
Interests Science, Chess, Literature, School, Science-fiction, Fantasy, Video games
First Appearance Changes
Final Appearance 2Geniuses 2Gether 4Ever
Voiced By Christine Cavanaugh (Seasons 1-2, first 6 episodes of season 3)
Candi Milo (Seasons 3-4)

Dexter is the main character and protagonist of Dexter's Laboratory. He is a boy genius who has a secret laboratory. His intelligence makes him the brains of the family and he is one of the world's greatest inventors, having created countless weird and amazing machines and experiments. He is always working on new inventions and creations every day, but his sister Dee Dee is always breaking into his lab and destroying his work. The daily events surrounding Dexter's life mainly revolve around his relationship with his sister and everything that happens between the two.


Dexter is a very short young boy who has curly red hair that was passed down to him from his mother He wears a pair of glasses that appear semi-circular at normal times, but when he widens his eyes, the tops of them round out. He wears a little white lab coat with black buttons on it. He also wears purple gloves, and a pair of black rubber zipper boots. Occasionally he may or may not wear a pair of black pants that match his boots. He speaks with a Russian accent despite the rest of his family not having any accents.


Dexter is an extremely intelligent boy (a self described "Boy Genius") who has been creating fantastic inventions since he was a baby. He considers Albert Einstein to be his greatest influence. He is normally in conflict with his sweet sister Dee Dee. Dexter, though highly intelligent, often fails at what he has set out to do when he becomes overexcited and makes careless choices. He manages to keep the lab a secret from his clueless, cheerful parents, who amusingly never notice any evidence of the laboratory, even when it was right before their eyes. Despite coming from a typical all-American family, Dexter speaks with a Russian accent (a reference to Genndy Tartakovsky's own accent that he spoke with during childhood and prank calls Rob Renzetti sent to Tartakovski while the two were at CalArts). Dexter's favorite superheros are Major Glory, Action Hank and Monkey (not realizing that Monkey is in fact his own lab monkey). Despite his great genius, Dexter is in fact very naive and occasionally very ignorant about certain subjects to the point where it seems like he lacks common sense; such examples of are his ignorance to the nature of girls, classic arcade machines and matters relating to nature, having not even known about famed biologist and friar Gregor Mendel the discoverer of DNA until Dee Dee told him, which clearly shows that despite his vast capabilities, Dexter is still a young and inexperienced child who lacks wisdom and experience. Dexter also has a huge ego which often clouds his judgement and has caused him to make rash and often morally questionable decisions, such as attacking Santa Claus due to his refusal to accept that he was real until the end, letting the Earth be destroyed do his inability to compromise with Mandark and even attempting to destroy Dee Dee for taking away his dream of saving the future, despite her having no malicious intent. As shown in Ego Trip, as Dexter grew older his personality went through numerous dramatic changes, such as the cowardly Number 12, the courageous Action Dexter and the wise but incredibly senile Old Man Dexter.


Birth and Early Childhood

Dexter's Birth

"At wast mother and father, I am created!" - A newborn Dexter

Dexter was first born in a hospital in Genius Grove. His Dad was so happy to have him until he found out that he had a very large head. He was terrified and hoping that there was nothing wrong with him. The doctors studied this and they found out that the reason for this was because he was a genius. His Mom and Dad were very happy to hear this and were very proud of him. The doctor gave him glasses in honor of his genius. With this proud declaration, his parents happily took him home to introduce him to his sister Dee Dee, who quickly began unintentionally tormenting the newborn Dexter.

The Family Together for the First Time

The family together for the first time.

As soon as Dexter could crawl, he immediately began to develop at a fast pace, building his first invention and studying technology, but Dee Dee kept on wrecking his inventions. This carried on until Dexter was 7 years old. Then, he found a secret place in his house that was empty and undiscovered.

Dexter's First Invention

Dexter with his first invention.

He decided to make this his secret laboratory and he would use it as a way to stay away from Dee Dee. One day, Dee Dee was playing in Dexter's Room while he was in his lab and then she saw the bookshelf that led to his lab. She then pulled the book out from the bookshelf and discovered Dexter's Lab for the first time. Ever since then, Dee Dee has been annoying Dexter and wrecking his lab.

The Dodgeball Incident

Meeting Mandark

Mandark and Dexter meet

Mandark and Dexter meet for the first time and thus begins their rivalry.

When Dexter started going to school at Huber Elementary School, he was recognized as the smartest kid there and the favorite of all his teachers. All of the teachers loved him and treated him like a friend. The other kids were even jealous of him for being so smart. This was until a new kid came along when Dexter went back to school for the new school year after summer break. The new kid was a young mysterious boy named Mandark who quickly became Dexter's rival. Upon their first meeting, Mandark proved that he was far smarter than Dexter and even won over the affections of Dexter's beloved teachers. To try and prove that he was still superior, Dexter showed Mandark his laboratory thinking it would mean that he's smarter than him, but then Mandark revealed that he had an even bigger and better laboratory. Mandark then forced Dexter to shut down his lab, or else become Mandark's lackey. Dexter thought that it was all over for him until Mandark fell in love with his sister Dee Dee. Realizing he could take advantage of this, Dexter told Mandark how to "invite" Dee Dee to his house by luring her with candy and entertaining her with "dancing", knowing full well that Dee Dee would go on a destructive ballet rampage if she was asked to dance.

Mandark's Lab Destroyed

Dexter watching Dee Dee destroy Mandark's lab.

After she arrived to Mandark's laboratory, Mandark quickly asked his beloved to dance, and as Dexter had anticipated, Dee Dee went on a dancing rampage and destroyed Mandark's laboratory. Dexter watched all this occur from his spy cams and he happily made a toast to his beloved and reactivated Computer who was happy to be back. After this event, Dexter had officially become the superior boy genius and Mandark became his eternally one-step-behind rival. This would be the beginning of Dexter's peculiar day-to-day life filled with wacky misadventures and many difficult challenges while trying to endure Dee Dee's antics and maintaining the secrecy of his lab.

Return of Mandark

A short time after his first encounter with Mandark, Dexter was at school when he announced that he would be taking part in the town science fair and the class praised Dexter's genius as he gloated about his superiority and his goal to win the science fair. An angry Mandark sitting in the back of the class was unable to hold back his frustration and called out everyone on their fanaticism towards Dexter and even told Mr. Luzinsky to hold his tongue, as he believed that Dexter was unworthy of any praise after he had destroyed his lab and used his feelings for his sister against him. Mandark then revealed that he planned to take part in the town science fair as well where he would defeat Dexter, however Dexter remained unfazed by his threats and ignored him even when Dee Dee tried telling him to be more cautious.

The next day during the fair, Dexter was about to win with his robotic arm until Mandark arrived dressed as a sorcerer and carrying a mysterious golden box. Mandark's late entry was accepted into the fair despite Dexter's protests and Mandark then used his dark brand of arcane magic to summon his inter-dimensional monster JoJo which then kidnapped Dee Dee, forcing Mandark and Dexter to put aside their differences and join forces to save her. After doing so, Dee Dee rewarded Dexter with a peck on the cheek and an amorous Mandark with a disturbed look and the two boys appeared to have settled their differences, at least until the two were given the blue ribbon prize. Their unwillingness to share the prize ended up re-igniting their rivalry once more.

Gooey Aliens Invade

Rushmore Rumble


Dexter in control of President Lincoln.

One day at school while watching a documentary on Mount Rushmore, Dexter discussed the possibility of bringing to life the presidential sculptures (after the subject was brought up by Timothy) with the technology of Tripolar Frankensteinian Electrodes which could then be used to cause havoc and destruction, and this thorough explanation did not go unnoticed by Mandark, who grew a keen interest in Dexter's explanation, writing down everything as he spoke.


Lincoln and George face off.

The next day as Dexter is planting a cherry tree, it is suddenly cut in half by a giant stone axe wielded by the now living full bodied statue of George Washington who is being controlled by Mandark. Mandark then has George smash Dexter's home and lab, forcing Dexter to briefly retreat. Dexter is then given a penny by Dee Dee which inspires him to travel to Mount Rushmore and bring to life his own sculpture.


Abe and George make peace.

Meanwhile Mandark, assuming himself to be victorious, proceeds to lounge in Dexter's pool with Washington when they are suddenly confronted by Dexter and his now animate statue of Abraham Lincoln. The boys and their statues then engage each other in an epic battle. Eventually the two statues prove to be evenly matched, and it appears the statues somehow gained self-awareness, commenting on their equal might and complimenting each other. The two eventually end the battle and leave behind Dexter and Mandark, much to their frustration, and the two statues decide to go eat some bricks.

Race Down Volcano Mountain

Rivals Unite

Sister vs Sister

Mandark little sister, named Olga Astronomonov, who goes by the name of "Lalavava", got into a rivalry with Dee Dee the same way Dexter did with Mandark after the two girls competed to get the solo role in the dance recital. After the solo was changed into a duet, the two girls sought out the aid of their brothers so they could build a device that would allow them to beat the other. However while Dexter was asked nicely by Dee Dee, Mandark was tormented and threatened by his sister. On the night of the recital, Dee Dee used the Dexo-Transformer while Lalavava used the Mandark-Transformer and each formed a deadly and destructive dance that destroyed the dance theater. Both then agreed that their brothers were stupid and that science stinks, and the two happily became friends and went to the mall.

Dexter Family vs Badaxtra


Dexter's family unites to defeat Badaxtra.

At a later point in his childhood, Dexter accidentally unleashed the unstoppable monster Badaxtra which threatened to destroy humanity. This forced him to reveal his laboratory to his parents as he needed their and Dee Dee's aid to pilot his greatest fighting robot, the Multi-Formic Megabot. At first they were no match for Badaxtra, but after uniting their hearts and joining forces with Monkey they were able to finally vanquish the vile beast once and for all. Luckily Dexter used his memory eraser ray to erase the memory of his lab from his parents minds. Monkey then used the ray on Dexter soon after so he would forget Monkey's real identity, however this also made him forget that he was the one who saved the day which caused Mandark to take all the credit.

Ego Trip

Rivals Becomes Archenemies

Rivals become mortal enemies.

For the next many years of his childhood, Dexter continued to have numerous crazy misadventures and weird encounters while constantly still having to deal with Dee Dee's annoying antics and trying to outwit Mandark. This would all change however with the creation of Dexter's greatest and most powerful invention ever, the Neurotomic Protocore, a device so powerful that it could revolutionize the world forever. The creation of this device caused Dexter's long time rival Mandark to go from being a mere opponent into a full blown evil archenemy due to realizing that with this device he could become the all powerful ruler of the world. He then became determined to steal Dexter's greatest creation and completely crush Dexter in order to achieve his goal of total supremacy, turning their once comedic and destructive rivalry into one of pure hatred and deadly force. Despite his many attempts, Mandark was never able to obtain the core during his childhood. It was during this time that Dexter was attacked by a group of robots who were seeking to destroy "the one who saved the future", believing that to be him, Dexter destroyed the robots and used his time machine to travel forward in time and see how he saved the future.



A young adult Dexter and Mandark begin their first day of work.

Many years later, a now teenaged Dexter and Mandark had been given jobs at the powerful world-conglomerate simply known as the The Corporation where they were made research scientists tasked with creating new ideas to make the future better. Early in their work, Dexter proved to be a creative machine who constantly came up with new and brilliant ideas while Mandark remained stuck with a creative block. Realizing that he was losing to Dexter, Mandark began stealing Dexter's ideas and presented them as his own to The Corporation's executives. This allowed Mandark to rise up the corporate ladder and overthrow the company heads. With this Mandark had taken over the entire company and had become Executive Mandark.


Dexter is reduced to the cowardly Number 12 after countless tortures.

Mandark had now become the richest and most influential person on the planet and during this time the world went through major technological and social changes and people everywhere had their names taken away and were instead given ID numbers. All numbers who worked directly under Executive Mandark were treated like mere work slaves and forced to obey his whim or else face physical punishment. Sadly not even Dexter was able to avoid this fate and was given the rank of Number 12 and was regularly subjected to Mandark's torture until he became a bumbling and cowardly shell of his former self, and with this Mandark had finally had his revenge but still he had not managed to find the long lost Neurotomic Protocore.

Number 12 Sob

Number 12 is "reunited" with what he once was, his younger and confident self.

Unbeknownst to the two, Number 12's younger self had traveled forward in time to see how "cool" he had become due to believing that he had saved the future. The young Dexter found himself inside his house which was now owned by complete strangers who quickly reported him to the police who planned to imprison him and make him do hard labor. Dexter was luckily able to avoid them but was soon confronted by a robot who identified him as Number 12. Dexter, realizing that Number 12 was his future self, allowed the robot to take him to what he believed was his corporation, but after finally meeting his future self, he was greatly disappointed.

Suiting Up

"What is your name?" "12?" "NO! What is your name?" "D-D-D-Dexter?" "Again!" "DEXTER!"

He then reminded his older self that he was once "Dexter, Boy Genius" and convinced Number 12 to help him overthrow Mandark. With a little of his old confidence restored, Number 12 took his beloved gloves from the compartment where he stored his long hidden Neurotomic Protocore and escaped his job with Dexter and traveled forward in time so they could meet their older self in hopes of finding out if they were really heroes and how they saved the future. Unknown to them however was that Number 12 had accidentally left his Neurotomic Protocore exposed, allowing Executive Mandark to get a hold of it and finally make his dark dreams a reality.

Traveling to Dextopia

Upon arriving to the far future, Number 12 and Dexter found themselves in a museum dedicated to them. They then discovered Mandark, or at least what was left of him, who was now known as Braindark and had apparently lost his body some time ago under unknown circumstances and had been imprisoned in the museum ever since. Upon being discovered by the museum's curator, he quickly recognized the two as the younger selves of the great leader, Dexter. They were then taken outside the museum and shown the land of Dextopia, Dexter's perfect future kingdom where all people were happy and healthy and had access to convenient technology.


The Dexters meet their elderly future self, Old Man Dexter.

The curator then took them to the palace of their older self and were greeted by a powerful booming voice, however it was quickly revealed that the voice was their frail future self, Old Man Dexter. Upon meeting each other, Dexter and Number 12 tried asking him how he saved the future, however Old Man Dexter could not recall, so the trio traveled back in time once more to find their middle-aged self and finally discover how they saved the future.

The World of Overlord Mandark


The Dexters arrive in an apocalyptic time period.

Once they arrived to their destination, they found their lab run down and practically destroyed and even worse they found the world in ruins and in despair, having now become a vast red wasteland. The trio eventually found a village of idiots and the young Dexter tried to give them some fire, but it was quickly destroyed by a legion of robots referred to as the "Overlord's Machine Men" which quickly began destroying the village. Luckily, a mighty and mysterious hero appeared on his motorcycle and quickly subdued the robots and gave fire to all the villagers to keep warm.


The three Dexters meet their cool middle aged self, Action Dexter.

The Dexters then realized that this mighty hero was in fact their middle-aged self, the mighty Action Dexter. The Dexters then asked their future self what had happened and he told them the tale of his youth and of what had happened to the world. Back when he was still Number 12 and he returned from his trip with his past and future selves, he had found that Mandark had stolen his Neurotomic Protocore (which Number 12 had left out before leaving with Dexter in his time machine). Mandark then tried harnessing the core's power but ended up setting its flow to negative, which twisted Mandark's already crooked mind and turned him into a being of pure power-hungry evil who now had the means to enslave the Earth. Unable to cope with the perversion of his creation, Number 12 fled underground and spent many years digging and living a subterranean life. During this time, the negative energies of the core caused the planet's inhabitants on the surface to become dimwitted idiots which allowed Mandark to easily take control of all the world's societies, technology and knowledge and hoard it all for himself, this allowed Mandark to become Overlord Mandark, the supreme ruler of the world.

Calm Before the Storm

The Dexters team up to create the ultimate mech while honoring the memory of their now destroyed lab.

When Number 12 re-emerged on the surface, and now having become powerful and muscular (and bald) due to all his years of intense digging and physical labor, he found the world "broken and stupid" and he began fighting the Overlord's robots and struggling just to survive.


The Dexters toast on the night before raiding the Overlord's castle.

With this knowledge in hand, the four of them teamed up knowing that they had to put a stop to Overlord Mandark's evil reign once and for all. The four Dexter's began work on their greatest and most versatile mech yet, a robot strong enough to help them storm Mandark's castle and finally take back the core. The next day, the four Dexters now in their new ultimate mech, arrived at Mandark's castle and quickly began to take down his army of robots. Unbeknownst to them, Overlord Mandark had been alerted of the arrival of the unknown mech.


The Dexters unite in their ultimate mech to storm Overlord Mandark's castle.

Angered that his law against the creation of technology that was not his own had been defied, his anger became more intense when he realized that the pilots were none other than his enemy Dexter and his timeline counterparts. With this knowledge, Overlord Mandark began to make arrangements to ensure his own victory. The Dexters continued their invasion of the castle and fought off countless robots, and despite suffering heavy damage, they were able to get past all of the castle's defenses and arrive in Mandark's chamber.


The ultimate mech enters the castle's domain and prepares to challenge its deadly security.

The gloating and obese Overlord Mandark welcomed the Dexters to his domain as he was lifted by his crane, but Action Dexter quickly made his intentions to overthrow him known. However Overlord Mandark remained unfazed and revealed his own counter against the Dexters using his own time machine which summoned young Mandark, Executive Mandark and Braindark to help him defeat the Dexters once and for all.

The Dexters vs

The Dexters prepare to battle the Mandarks.

The Dexters and the Mandarks quickly confronted one another while Overlord Mandark and Action Dexter exchanged witty banter, commenting on how this reunion reminded them of old times. The young Dexter however silenced them and demanded to have his core returned. The Mandarks and the Dexters then faced off against their respective time counterparts. The young Dexter and Mandark had a rather childish exchange of fisticuffs, Executive Mandark easily overpowered Number 12 due to his weak insecurities, Overlord Mandark and Action Dexter exchanged heavy blows, and Braindark and Old Man Dexter exchanged petty insults.

The One who saved the Future


With newfound resolve and the Mandarks briefly subdued, the Dexters prepare to end Overlord Mandark's reign once and for all.

At first the Mandarks seemed to have the advantage, but the Dexters quickly turned the tide in their favor when Number 12 had finally had enough of Executive Mandark's abuse after he crushed his glasses which unleashed his inner might and confidence which allowed him to completely pulverize Executive Mandark and take his glasses. Now finally having become Dexter once more, Number 12 Dexter told them that if they set the Protocore back to a positive flow then everything would return to normal.


Dexter, a push away from becoming the one who saved the future...

With this turn of events, the Dexters quickly overpowered their Mandarks, with Action Dexter using his wrench to unhook Overlord Mandark from his crane which made him immobile, young Dexter using his wrench to pinch young Mandark's nose, and Old Man Dexter ignoring Braindark's insults and using his wrench to get back on his feet. The Dexters then made their way to the core as the Mandarks yelled for them to stop. Overlord Mandark then summoned his bulldozer to carry him and he and the other Mandarks regained their composure and stopped their respective Dexter from reaching the control panel of the core.


... until Dee Dee arrives and unknowingly takes the glory.

As the Dexters struggled to reach the button they began chanting "Go Dexter Go!" to cheer each other on as young Dexter began to slowly reach the positive flow button. Just then, a time-traveling Dee Dee appeared from Dexter's Time Machine which was attached to the broken mecha, and she quickly made her way past the Dexters and Mandarks. As she passed them, the Mandarks briefly reverted to their old selves and swooned over their long lost beloved Dee Dee. Dee Dee then saw the positive flow button and her innate curiosity made her push it, which resulted in her saving the future much to the grief and anger of the Dexters.


The Dexters stand victorious and rest assured that their robots will stop Dee Dee.

With the positive flow coming from the core, the world became green and vibrant once more and humans were once again intelligent, and the Mandarks were zapped back to their own time while Overlord Mandark exploded and all that remained was his brain, turning him into Braindark. Mandark's castle then crumbled and all seemed well, until the Dexters arose from the wreckage, angered at having realized that Dee Dee was the one who saved the future, having taken the glory from them. The Dexters in their anger quickly invented transforming robots that would go back in time and destroy Dee Dee for ruining their adventure.


Dexter discovers the unusual predestined paradox, but decides to forget about it.

With that matter over with and the world free of Mandark's clutches, Action Dexter swore to use the Neurotomic Protocore for good and rule the world with a fair and just hand. After this, all of the Dexters returned to their normal times before fondly bidding farewell. After Action Dexter located Mandark's brain and put it in a jar with a communicator (where he would spend the rest of his days as punishment for his crimes), Action Dexter began the creation of his new civilization, Dextopia where he would share his knowledge, technology and his technically unearned status of "savior of the future" with all. Upon returning to his own time, young Dexter saw his past self from earlier fighting the very same robots who had come to destroy "the one who saved the future" which were in fact the robots he had created to destroy Dee Dee, which caused him great confusion due to the time anomalies.

Dexter ignores Dee Dee for the last time

Dexter ignores Dee Dee for the last time.

Regardless, young Dexter preferred to forget about it and go have a sandwich, and he proceeded to ignore Dee Dee.

Later Years


An elderly Dexter content with his life.

Dexter would continue to live out his life from that point on and experienced life as the downtrodden Number 12 and the heroic Action Dexter before finally becoming the elderly ruler of his kingdom of Dextopia, Old Man Dexter and living out his golden years as the somewhat senile ruler of the world with his sister Old Gal Dee Dee.


  • Dee Dee - Dexter is normally in conflict with his sweet older sister, Dee Dee, who always mysteriously gains access to his lab no matter what he does to keep her out. Dee Dee eludes all manner of security and, once inside, delights in playing in the lab, often destroying all of his creations, often by pushing the wrong buttons on an invention. This is often preceded by Dee Dee asking "Oooooh, what does this button do?", without waiting for an answer. Despite her hyperactive personality, Dee Dee sometimes makes more logical decisions than Dexter, or even gives him helpful advice. Despite being excessively irritated with Dee Dee due to her constant interference and stupidity, Dexter still loves her and cares about her well being, and even saved her life numerous of times. However his anger towards Dee Dee often gets the best of him and it has resulted in him often trying to get her out of his life, due to the point of willingly giving her to aliens and even trying to destroy her in "Ego Trip" for stealing his role of savior of the future from him. But in the end, Dexter always somehow manages to forgive her and vice-versa and the two remained close siblings even into their elderly golden years.
  • Mandark - Dexter has a strong rivalry with Mandark which eventually developed into a deep hatred over time and the two became arch-enemies. The reason for this animosity is due to Mandark's attempts to constantly try to shut down or destroy Dexter's lab or even steal one of his inventions to prove that he is smarter than him. Although Mandark isn't as recurring of a conflict as Dee Dee is, Mandark is even worse of an enemy than Dee Dee. They sometimes compete to see who's smarter, and while Mandark was the superior mind when they first met, Dexter eventually proved to be superior and has continued to win against Mandark since their first meeting, although sometimes the two may end up in a draw, for instance in the episode where Monkey and Quackor were both fighting and Dexter and Mandark were going to turn them into class but both ended up failing. The rivalry between them eventually turned into one of pure hate and villainy when Dexter created his greatest work, the "Neurotomic Protocore" which could change the world. When Mandark realized the tremendous power this invention could give him, he turned into an evil and megalomaniacal villain who sought only power and the total destruction of Dexter at all costs.
  • Monkey - Dexter is always trying to make Monkey do something amazing but no matter what he does to him, Monkey just stays a mere monkey, but whenever Dex isn't looking, monkey changes into an amazing superhero and that power is somehow able to elude all of Dexter's most observant and flawless of machines. Dexter is not aware of his Monkey's superhero identity, which he idolizes as much as his other heroes.
  • Dad - Dexter's father normally tends to show favoritism to Dee Dee due to her athletic prowess, but will occasionally side with Dexter when facing a challenge between the sexes. Dad is also depicted as unreasonably hostile towards Dexter when he interferes with a sports-related activity such as watching the "biggest golf match of the year" or breaking his bowling trophy. Despite all this, Dad has proven to be closest to Dexter, to the point where he was more than happy to make Dexter "destroy" Dee Dee in a snowball competition and appeal to Dexter to give him his desired muffins to the point where he could seemingly control Dexter. He has also gone to great lengths to show his love for his son, showing that he has a very close bond with Dexter.
  • Mom - Dexter appears to be fairly close to his mother, and appears to have inherited his intellect from her side of the family (specifically from her [[Grandpa|father). He is sometimes embarrassed by her, such as when she kept causing a ruckus at a chess tournament in an effort to cheer him on and ended up getting him disqualified. However at times it has been shown that Dexter greatly fears her and she has shown to be even more hostile and harsh than Dad when it comes to punishments and may even become extremely angry over the slightest objection that Dexter may have.
  • Douglas E. Mordecai III - Douglas E. Mordecai III is Dexter's closest friend. He is a genius just like him, although Dexter appears to be the smarter of the two as Douglas doesn't seem have his own secret laboratory (at least not that we know of) so Douglas is only a nerd while Dexter is more of a super genius. Regardless, it appears that Douglas knows of Dexter's high-tech inventions and admires his buddy for them.
  • Koosalagoopagoop - At first, Dexter was incredibly annoyed with Koosy to the point where he tried "unplugging" him and imagining him away forever, but in the end, he realized that Koosy was indeed a sweet and loving creature and quickly hugged him before he disappeared, much to his regret. In seasons 3 and 4, Koosy and Dexter were reunited, but Dexter was once again hostile towards Koosy for unknown reasons, but in the end the two became friends once more.
  • Major Glory - Dexter is a huge fan of Major Glory. He regularly watches his show, reads his comic books, plays with his toys, and loves everything that's related to him. Major Glory is Dexter's entertainment idol. Dexter has even met Major Glory in person on certain occasions such as the episodes Star Spangled Sidekicks and Figure Not Included.
  • Action Hank - Next to Major Glory, Action Hank is an iconic character that Dexter is obsessed with and has a vast amount of respect and admiration for. Dexter loves watching Action Hank's show and desires to be just like him, a wish that eventually comes true in the far future. He has met him in person in the episodes Action Pack, A Beard to be Feared and Decode of Honor and the two became good friends that know each other well.


In the What-A-Cartoon shorts, Christine Cavanaugh served as the voice of Dexter, and returned to voice the character when the show was picked up, and remained on the show throughout the first two seasons, and the first few episodes of season 3. However, Cavanaugh retired from voice acting after the season 3 premiere, and was replaced by Candi Milo, which some fans did not immediately take to heart, as they claim she made Dexter's voice sound forced and cheesy. However, they noted an improvement in her rendition of Dexter in Season 4.


  • "Dee Dee" - Various Episodes
  • "Ahhh, what a fine day for SCIENCE!" - Various Episodes
  • "Dee Dee! Get out of my laboratory!" - Various Episodes
  • "At last, my greatest creation is now completed!" - Various Episodes
  • "Dee Dee No! Don't push that button!" - Various Episodes
  • "SHUT UP! SHUT UP! SHUT UP!" - "Monstory"
  • "This better be important woman, you are interrupting my very delicate calculations." - "Deedeemensional"
  • "Ahhh, what a wonderful day for I Dexter, boy genius to be working in my laboratory." - "Opposites Attract"
  • "Success!" - Various episodes

Episode Absences


Dexter clothes
Dexter's gallery can be viewed here


  • Dexter's voice actor is Christine Cavanaugh and Candi Milo in the series, but in Cartoon Network: Punch Time Explosion, it is Tara Strong, who is the voice of Bubbles from Cartoon Network's The Powerpuff Girls.
  • Dexter's last name has never been revealed throughout the entire series.
  • In the episode Go Dexter Family Go!, Dexter says his favorite color is orange, but in a previous episode he stated his favorite color was blue.
  • Dexter speaks with a Russian accent, although the rest of his family doesn't.
  • Dexter's age is never mentioned in the series, but according to the song "Love According to Dexter", Dexter is said to be 8 years old.
  • Dexter's astrological sign was first shown to be Capricorn in the episode "A Hard Day's Day," but the season 3 episode "Mind Over Chatter" lists his birthday as March 24, which would actually make him an Aries.
    • However as seasons 3 and 4 were not overseen by series creator Genndy Tartakovsky, the validity of his birth date in said episode is questionable and was likely just an oversight by the staff in season 3.
  • In seasons 1 and 2, Dexter had a longer head and a double chin and there were two visible buttons on his lab coat, but in seasons 3 and 4, he had a shorter head, no double chin, and had only one visible button.
  • Although Dexter is the main character, there have been many episodes where he has not appeared.
  • Dexter has made many cameos in episodes of The Powerpuff Girls. The reason for this is possibly because the creator of The Powerpuff Girls, Craig McCracken helped with making Dexter's Laboratory before he created The Powerpuff Girls.
    • In the episode "Powerpuff Bluff" Dexter was seen sleeping with the other kids at Poakey Oaks Kindergarten.
    • In the episode "Criss Cross Crises" when Professor Utonium was switching peoples bodies trying to turn them back, one of the people Mrs. Bellum switched bodies with was Dexter.
    • In the episode "Forced Kin" when it showed the people that were looking up at Mojo Jojo's giant robot, one of them was Dexter.
    • In the episode "Ploys R Us", Professor Untonium was seen getting a stuffed toy of Dexter as well as stuffed toys of Dee Dee and Monkey.
  • In the episode "Dexter's Wacky Races" Dexter had a car that he invented in his laboratory that he was using in a race that has his parents in it. This means that he was exposing something from his lab to his mom and dad, although he and his parents were never directly in front of each other nor did they make any interaction with each other in the episode.
  • In the episode "Tribe Called Girl", Dee Dee said that Dexter had special needs, however whether she said this mockingly or if Dexter has an actual disorder remains uncertain.
  • Dexter's glasses are flat on top when he is feeling content or angry, but when he is shocked or scared, his glasses become rounded at the top.
  • He has appeared in a variety of Dial M for Monkey episodes such as, Magmanamus, Peltra, Simion, Quackor and Last But Not Beast.

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