Dexter's Laboratory began as a short in Cartoon Network's showcase of new cartoons and became the channel's first full original series in 1996. It followed Dexter, a short boy genius with a thick accent and a huge secret laboratory behind his bookcase, and his endlessly cheerful sister Dee Dee, who always found a way in.
Quick answer
The main Dexter's Laboratory characters are Dexter, a boy genius with a secret lab, his big sister Dee Dee, their Mom and Dad, Dexter's next-door rival Mandark and the lab's Computer. The show also featured Dial M for Monkey and The Justice Friends segments with characters like Monkey, Agent Honeydew, Major Glory, Valhallen and Krunk.
The family
| Character | Who they are |
|---|---|
| Dexter | A boy genius with a secret laboratory and big ambitions |
| Dee Dee | His tall, ballet-loving older sister who loves pushing buttons |
| Mom | Cheerful, cleanliness-obsessed mother |
| Dad | Goofy, sports-loving father |
Rivals and lab
| Character | Who they are |
|---|---|
| Mandark | Dexter's rival genius next door |
| Computer | The lab's talking computer |
| Lab robots and inventions | Clones, robots and gadgets that often go wrong |
Dial M for Monkey
| Character | Who they are |
|---|---|
| Monkey | Dexter's lab monkey, secretly a superhero |
| Agent Honeydew | Monkey's mission handler |
The Justice Friends
| Character | Who they are |
|---|---|
| Major Glory | Patriotic superhero |
| Valhallen | Rock-and-roll Norse god |
| Krunk | Gentle giant with a temper |
Why Dexter's Lab mattered
Dexter's Laboratory helped define Cartoon Network's identity. Its sharp writing, retro-inspired art and sibling rivalry humor made it a hit, and its success led to more creator-driven originals like The Powerpuff Girls and Johnny Bravo.
Fun fact: Dexter's lab is hidden behind his bedroom bookcase, and his parents somehow never notice it.
The sibling rivalry at the heart of the show
At its core, Dexter's Laboratory is a sibling comedy. Dexter wants order, secrecy and scientific glory; Dee Dee wants to dance, play and press every button she can find. Almost every episode turns on that tension, and the joke is that Dee Dee, for all her chaos, often wins, either by accident or by being smarter than Dexter gives her credit for.
The supporting cast adds layers. Mom and Dad are cheerfully oblivious to the giant laboratory behind the bookcase, which makes the secret feel even funnier. Mandark, introduced as a rival genius next door, mirrors Dexter's ego and gives the show an ongoing villain, complicated by his crush on Dee Dee.
The show's style also matters. Bold shapes, limited colors and retro sci-fi details gave it a distinctive look, and the voice acting, especially Dexter's exaggerated accent and Dee Dee's sing-song voice, made the characters instantly recognizable. Many fans can still quote their favorite lines word for word.
For costume ideas, Dexter and Dee Dee are among the easiest 90s cartoon characters to recreate: a white lab coat, gloves and glasses for Dexter, and a pink leotard and blonde pigtails for Dee Dee.
Conclusion
The Dexter's Laboratory characters remain favorites for 90s kids. See more in 90s Cartoon Network shows and Powerpuff Girls characters.
Frequently asked questions
Who are the main Dexter's Laboratory characters?
The main characters are Dexter, a boy genius, his older sister Dee Dee, their Mom and Dad, Dexter's rival Mandark and the lab's Computer.
When did Dexter's Laboratory premiere?
Dexter's Laboratory premiered as a series on Cartoon Network in April 1996 after starting as a short.
What is Dee Dee's catchphrase?
Dee Dee is famous for asking "Ooh, what does this button do?" before causing chaos in the lab.
Who is Mandark?
Mandark is Dexter's rival, a fellow boy genius who lives next door and has a crush on Dee Dee.
What were the other segments in Dexter's Laboratory?
Early seasons included Dial M for Monkey, about Dexter's lab monkey secretly being a superhero, and The Justice Friends, a sitcom about superheroes sharing an apartment.
Sources and further reading
Dates and facts were checked against these references. Release dates can vary by region; we use North American dates unless noted. Spotted an error? Tell us.