Dexter's Laboratory Wiki

“Ooh! What does this button do?”
Dee Dee

Dee Dee
Aliases Princess Dee Dee, Stupid Sister, Blockhead, Golden Haired Angel, Pink Pussy Willow, Racer D, Diva Dynamite, Deestructa, Old Gal Dee Dee
Gender Female
Species Human
Family Dexter (Brother)
Mom (Mother)
Dad (Father)
Grandpa (Maternal grandfather)
Fergle O'Reilly (Maternal uncle)
Dextamina (Great-aunt)
Occupation Ballet Dancer, Student
Interests Pony Puff Princess, Ballet, Dexter's Lab
First Appearance Changes
Final Appearance Babe Sitter
Voiced By Allison Moore (season 1)
Kat Cressida (season 2)
Allison Moore (season 3)
Kat Cressida (season 4)

Dee Dee is a main character and the secondary protagonist in the series, Dexter's Laboratory. She is Dexter's older sister, who is mostly seen destroying or ruining Dexter's lab in various ways. The daily events surrounding Dee Dee's life mainly revolve around her relationship with her brother and everything that happens between the two.


She is two to three times taller than Dexter and has peculiar body proportions; a minuscule torso with a large head and gangly limbs, similar to a ballerina's. To complete the ballet look, she wears a rose/brink pink colored small tutu, white pantyhose and pink ballet pumps, which usually create a "squishy" noise while walking. She has a similar personality and hair color to her father. For sleeping she wears a pink nightgown, and she wears her hair down. For swimming she wears a pink one-piece swimsuit and a pink swimming cap with the initial 'D' on the front. She has fair skin, blue eyes and long blonde hair in pigtails.


Dee Dee is Dexter's extremely ditzy, simple-minded, energetic, hyperactive older sister. She usually, in one way or another, sabotages his experiments and destroys his lab in every episode of the show, although she does so out of ignorant curiosity rather than malicious intent and she in actuality loves and cares for her brother dearly. Though she was shown to get hypocritically angry when she found that Dexter had been in her room and messed with her stuff. Dee Dee also loves ballet, puppies, unicorns, playing dolls with her friends, messing around in Dexter's laboratory and generally depicts all the stereotypes concerning normal girl activities. Dee Dee has a great love and fascination for buttons to the point that her catch-phrase is "Oooooooh, what does this button do?". She rarely wears her full length of hair down except on rare occasions, mostly when sleeping, preferring to keep them in their recognizable style. She also has a multitude of stuffed animals and adorable girl's toys that she loves dearly and is very protective of. It was revealed in the episode "A Hard Day's Day" that Dee Dee's astrological sign is Cancer, indicating that she was born somewhere between June 22nd or July 23rd.

Despite her usual ignorance and incredible stupidity, Dee Dee has been shown to actually be a very wise girl for her age who displays far better common sense than her brother and less naivety about subjects that Dexter is completely ignorant about. Dee Dee has a far better understanding of nature and inner peace than her brother as well as apparent knowledge of important biological and botanical subjects, being very familiar with the achievements of biologist and friar Gregor Wendell who even Dexter was completely ignorant of. In the end, Dee Dee is a loving girl with a strong love for her brother and despite his attitude towards her and attempts to get rid of her and even destroy her, she has continued to stick by him long into her elderly years, and unlike him was able to avoid senility and still take care of him with love and kindness.


While Dee Dee lacks Dexter's skills in technology and science, she has shown to posses a powerful imagination that can even bring imaginary creatures to life, and she can even travel to the imaginary world of Koosland and interact with imaginary creatures such as the Koosalagoopagoop. In seasons 3 and 4, she is also made the creator of Koosland. Dee Dee has also displayed the unusual ability to see into the future as revealed in "Chubby Cheese" and communicate with certain animals.


Birth and Early Childhood


"It all started when you were a dumb little baby. Your mind was a complete blank." - Koosalagoopagoop

Dee Dee was born sometime before her brother between June 22nd and July 23rd. According to seasons 3 and 4, when an infant Dee Dee had her first thought, she created the imaginary being Peepers who then began to create the world that would be the host to all of Dee Dee's imaginary creations, Koosland. At an unknown point, Dee Dee would eventually come to meet the imaginary dragon, Koosalagoopagoop who she affectionately called Koosy.

The Family Together for the First Time

The family together for the first time.

When she was still a crawling toddler, her mother became pregnant and would eventually go to a hospital in Genius Grove to give birth while Dee Dee stayed home. After her parents happily returned home with their newborn son Dexter, they introduce him to Dee Dee for the first time who was more than overjoyed at the sight of her brother, however she quickly began unintentionally tormenting the newborn Dexter after poking his bellybutton. Thus beginning their eternal sibling conflict.


An infant Dee Dee about to ruin Dexter's first invention.

Throughout most of their infancy, Dexter would try to build unique inventions while Dee Dee kept on wrecking them with her naive curiosity. This carried on until Dexter was 7 years old. Then, he found a secret area within his house that was empty and undiscovered. 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 pretending to be the sea captain of a ship called the Pea when she discovered a mysterious bookshelf that had never been in Dexter's room before. She then pulled a book out from the bookshelf and discovered Dexter's Lab for the first time. From that point on, Dee Dee has continued annoying Dexter and wrecking his lab ever since.

Meeting Mandark

Mandark and Dee Dee Meet

Mandark meets his beloved Dee Dee for the first time.

One day, Dee Dee unknowingly came in contact with the individual that had become Dexter's eternal rival, Mandark, who proved to far outclass Dexter and even managed to shut down his lab, which made a defeated Dexter believe that it was all over for him until Mandark fell in love with the golden haired angel, Dee Dee, having become completely captivated by her blessed beauty. 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. After following a mysterious trail of candy, Dee Dee arrived at Mandark's laboratory and 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.

Dee Dee's Destructive Dance

Dee Dee begins her destructive dance with Mandark.

After this event, Dexter had officially become the superior boy genius and Mandark became his eternally one-step-behind rival who remained completely in love with Dee Dee, who was unwilling to return his affections. This would be the beginning of Dexter and Dee Dee's peculiar day-to-day life filled with wacky misadventures and many difficult challenges, although Dee Dee was more than happy just spending time with her brother and innocently wrecking his lab while avoiding Mandark's advances.

Return of Mandark

A short time after their first encounter with Mandark, Mandark took part in the town science fair using his arcane magic in hopes of winning the show and having his revenge on Dexter. During the fair, he summoned his monster JoJo which then kidnapped Dee Dee, forcing Mandark and Dexter to 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. The two are then given the blue ribbon prize and were unwilling to share due to their rivalry.

Dee Dee's Rival

Dee Dee and Lalavava Meet

Dee Dee and Lalavava meet, starting a fierce rivalry.

At a later point on the day of the important dance recital tryout, Dee Dee prepared to give it her all to get the solo role in the dance recital. However it was on this day that she met her own rival, Lalavava, Mandark's diminutive sister. The two then danced against each other to prove their skills, but their dance teacher Ms. Babcock was so pleased with their abilities that she decided to turn the solo into a duet, much to their annoyance. It was at this time that Dee Dee decided to ask for Dexter's help in order to use his inventions to out-dance Lalavava. At the same time, Lalavava threatened her own brother to do the same.

Dee Dee and Lalavava become friends

Despite their heated rivalry, the two girls bury the hatchet and become friends.

At the night of the dance recital, the two arrived equipped with the Dexo-Transformer and the Mandark-Transformer and began a rampaging dance battle that destroyed the dance stage. In the end, neither received any praise for their destructive dance and lost all the glory to the backup dance. Dee Dee then asked her if she too had an annoying genius brother and both agreed that science stinks. The two then became good friends and decided to go to the mall.

Dexter Family vs Badaxtra


Dexter's family unites to defeat Badaxtra.

At a later point in their childhood, Dexter accidentally unleashed the unstoppable monster Badaxtra which threatened to destroy humanity which forced him to reveal his laboratory to his parents as he needed theirs 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. However Dee Dee's memories remained in tact but she was more than happy with keeping the truth to herself.

Dee Dee and the Dreamwish-O-Tron

After having had enough of Dee Dee's tomfoolery, Dexter invents the Dreamwish-O-Tron 5000, a device that can make one's fondest dreams come true, which he plans to use to finally be rid of Dee Dee. Once Dexter dreams of a world without Dee Dee, his wish becomes a reality, but as time passes he realizes that he misses his dear sister and decides to get her back. As he had planned for this, the device was not programmed to completely erase her, but instead send her to a different reality that suited her needs and where her mind would be altered to make her believe she had always been a resident of that reality.

Upon tracking down her location and traveling there, Dexter finds himself transported to a girly fantasy world filled with all the things Dee Dee would love. As it turns out, Dee Dee has been made the queen of this world, and Lee Lee and Mee Mee have been transported here as well, serving Dee Dee as her personal guards and advisers, likely having been wished away as well due to their strong similarities to Dee Dee, a fate which also befell many other girls who shared anything in common with Dee Dee. Once Dexter confronts them, Dee Dee, Mee Mee and Lee Lee have no recollection of who Dexter is. As Dexter tries to make Dee Dee remember, she has Lee Lee and Mee Mee throw Dexter into the dungeon for disturbing the peace.

Ego Trip

Mandark stares at Dee Dee

Mandark gazes at his beloved Dee Dee before the event that will change everyone's lives.

For the next many years of their childhood, Dee Dee and Dexter continued to have numerous crazy misadventures and weird encounters while constantly getting into disputes 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 villain due to realizing that with this device he could become the all powerful ruler of the world.

Dee Dee and Dexter part ways

Dexter tells Dee Dee to leave his lab, unaware of the consequences that will unfold because of it...

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, however he would still retain his undying and pure love for Dee Dee. Despite his many attempts, Mandark was never able to obtain the core during his childhood.

Dee Dee Time Travels

... and Dee Dee leaves via the time machine, thus beginning a grand series of events.

It was during this time that Dexter had told Dee Dee to "get lost" after annoying him too many times, and while annoyed, she complied with his request and proceeded to leave by using his time machine to "get lost". As soon as she disappeared, a group of robots appeared from the same time machine and were seeking to destroy "the one who saved the future". Dexter believed this to be himself and so he destroyed the robots and used his time machine to travel forward in time and see how he saved the future while being unaware that Dee Dee had also traveled through time. Along the way he would meet and team up with future versions of himself on an adventurous quest to stop the evil Overlord Mandark and save the future from his reign, although strangely enough, he never encountered a future version of Dee Dee while on this adventure.

Dee Dee saves the Future

Dee Dee Arrives

After so long... Dee Dee finally arrives.

Dexter and his future selves, Number 12 and Old Man Dexter teamed up with their middle aged self Action Dexter and prepared to take down Overlord Mandark. 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 and the Mandarks quickly faced off and at first the Mandarks seemed to have the advantage, but the Dexters quickly turned the tide in their favor and they made their way to the corrupted Neurotomic Protocore 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.

Dee Dee captivates the Mandarks

With Dee Dee's arrival, the Mandarks become overwhelmed by their love for her, leaving them powerless.

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 past them, the Mandarks briefly reverted to their old selves and swooned over their long lost beloved Dee Dee.


Dee Dee unknowingly steals the glory from her brother.

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, all having been made possible by Dee Dee's oblivious actions. 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 and had 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 after fondly bidding farewell. 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 proceeded to ignore Dee Dee.

Later Years


An elderly Dee Dee content with her life.

Dee Dee's life past her childhood is mostly a mystery as her future selves were never seen during Dexter's journey through time. However, it is known that she did manage to survive the many trials and catastrophic events caused by Mandark's future self and she eventually grew to a cheery and elderly age and peacefully lived out her life with her brother Old Man Dexter with whom she still shared a close bond despite their continued differences.


Although she seems to be extremely ditzy, her social skills far exceed Dexter's, as she is quite popular at their local school while he is shunned by everyone with the exception of his other equally geeky associates.

  • Dexter - Dexter is Dee Dee's little brother. She loves "playing with," him but she destroys things in his lab and drives him crazy. It may seem that Dee Dee is nothing but a pure idiot who just annoys Dexter all the time, but truthfully deep down inside of her candy canes and lollipop glitter heart, she loves Dexter and thinks he's awesome. In fact, to her, Dexter is her favorite thing in the whole entire world. This was seen in the episode "Game Show" where the Game Show host asked what their favorite things in the world were and Dexter is what Dee Dee chose. When Dee Dee comes into the Laboratory, she never wants to destroy any of his inventions or ruin any of his experiments. What she really wants out of all that, is to spend time with her little brother Dexter and to spend time with him in their early years of that short and brief section of life called childhood. Dee Dee is really a lot smarter than she comes on to be, Dee Dee is really a smart girl and she is smart enough to know that if Dexter doesn't get out of his lab more often and see the world, he will have wasted his life trapped inside of his lab. Sometimes she wants him to come outside which she does and clearly explains in various episodes such as Way of the Dee Dee. She wants him to see the world and realize what a wonderful and perfect thing life is and to have him experience the best things in life and a lot of the time, Dee Dee's reckless little antics are actually the things that make Dexter do those good things in life. It may be possible that she does this intentionally because she knows what the outcome would be, some would even say she is smarter than Dexter.
  • Lee Lee & Mee Mee - Lee Lee and Mee Mee are Dee Dee's two best friends in the series. Their two young girls that share her interests, personality, fashion sense, and even similar names. Dee Dee, Lee Lee, and Mee Mee are just like each other. They always spend their time just being girls and having fun. The three of them all go to the same ballet classes together where they are the three best students with Dee Dee being the best, Mee Mee being the second best, and Lee Lee being the worst.
  • Dad - Dee Dee is very close to her father, and it appears that both she and Dexter are closer to their father than with their mother as they are often seen sharing and doing more activities with him than with Mom. While Dad has shown to prefer Dexter over Dee Dee on several occasions, he is clearly more proud of Dee Dee's sports-based accomplishments and her willingness to play sports with him, showing that he cares for her just as much as Dexter. However whenever he goes into his psychotic muffin episodes, he and his children become quite distant.
  • Mom - Dee Dee loves her mother as much as her father and Mom has shown to become quite angry at Dexter when he refuses to play or take care of her sister, showing that she cares quite a lot about her, however, like with Dexter, she will not hesitate to scold and punish Dee Dee angrily should she question her or behave questionably. Mom has also shown to be quite proud of Dee Dee's dancing ability and even attends her ballet recitals.
  • Koosalagoopagoop - Koosy is Dee Dee's imaginary best friend whom she loves to play with and both often have adventures together and Koosland. Dee Dee is the only one who can see Koosy because she is the only one who believes in him. He is completely invisible to others unless she makes them believe which she did to Dexter.
  • Lalavava - Lalavava is Dee Dee's worst enemy. The way she and her act toward each other is just about a mirrored relationship to that of Dexter and Mandark's. However they eventually managed to end their rivalry on a good note unlike their brothers after agreeing that they both hated their brothers and their destructive science. They then became good friends and went to the mall together.
  • Oceanbird - Oceanbird once hired Dee Dee to babysit Mandark. She likes her and thinks of her as a friend to the family despite her rivalry with Lalavava.
  • Monkey - Whenever Monkey is not in his secret supehero form, he pretends to be an ordinary lab monkey. Dee Dee is sometimes seen playing with Monkey and dressing him up in girly costumes and having tea parties with him despite him being a male monkey. Monkey doesn't seem to be bothered by this and appears to enjoy playing with her as it is one of the few times where he can happily goof off and have fun aside from his dates with Agent Honeydew.
  • Beau - Beau is Dee Dee's love interest and ex-boyfriend. He was first seen in the episode Beau Tie.


Originally voiced by Allison Moore, the role was assumed by Kathryn Cressida after the first season. Moore reprized the role in the third season, with Cressida taking it back for the show's fourth season. Tara Strong, who voiced Bubbles from The Powerpuff Girls, voiced Dee Dee in the MAD episode, Once Upon a Toon.


  • "Hi Dexter!" - Various Episodes
  • "Ooooooh! What does this button do?" - Various Episodes
  • "Good Night" - Various Episodes
  • "Oh Dexter, Dexter come quick! You sent me, and me!" - Dee Dee Dimensional
  • "But I want to push the button." - Dexter's Assistant
  • "Your club is for big I D K S C's" - Decode of Honor
  • Don't be silly! I love you very much! - LaBretto
  • Oops! I guess I shouldn't touch! - LaBretto
  • "Play with you Dolly Susie" - Babe Sitter
  • "Fine! I don't need your stinkin' lab, i've got my own stinkin' lab!" - Dee Dee's Lab
  • "Hello, dear brother! What have you got there? - LaBretto


Dee Dee Ego Trip
Dee Dee's gallery can be viewed here


  • Dee Dee's favorite color is pink.
  • While Dee Dee's birthday is never stated outright, it was implied that she is a Cancer as shown in the episode "A Hard Day's Day."
  • Her feet are very large, this is addressed throughout the series, and in the episode "Shoo Shoe Gnomes" she is seen to have high-rampant foot odor.
  • A running gag in the series is Dee Dee showing Dexter her "new" dance called "the Fanciful Unicorn" over and over again, forgetting she has already showed him many times.
  • Dee Dee has two friends named Lee Lee & Mee Mee who both look like her and have similar sounding names.
  • She has been called a "golden haired angel" by both Mandark and Nice Dexter.

Site Navigation