The Justice Friends are a group of superheroes who exist in the universes of Dexter's Laboratory and The Powerpuff Girls and occasionally appeared in back-up segments of Dexter's Laboratory. The Justice Friends is considered to be a spoof or a parody for DC Comics Justice League and Super Friends, and Marvel Comics Avengers.
- Major Glory is a semi-effective, caped American hero given to over-dramatic, patriotic dialogue. He is a parody of both Captain America and Superman. His love for publicity and of the paparazzi can often present more harm than good. His secret identity is concealed by several masks instead of just one, he is the nephew of Uncle Sam who is currently a hippie, and he is allergic to cats. He is voiced by Rob Paulsen.
- Valhallen is a guitar-wielding Viking god of rock with Southern Californian mannerisms. He is a parody of both the Mighty Thor and rock music guitarist Eddie Van Halen. Val Hallen's guitar is his source of divine power, as seen in the episode Val Hallen's Room where he was reduced to a nerd having lost it. Upon finding it, the power of the guitar restored him to his true form. However, it seems that the guitar itself does not supply an infinite amount of energy as he had to retrieve his power when Mental Mouse claimed it in the episode Can't Nap. It's also powered by static electricity as well. Valhallen can also fly on his guitar, much the same way Mjolnir grants Thor the ability of flight in the Marvel Universe. It can be noted that his guitar bears resemblance to the Gibson Flying V most likely an inside joke for guitar players. He has been seen using various means of transportation throughout the series, such as a cross between a Viking longship and a jeep, or a chariot pulled by a goat named Billy, similar to the chariot used by Thor in Norse mythology which is pulled by two goats. He is voiced by Tom Kenny.
- Infraggable Krunk is an overgrown muscle-man with arrested mental development. He parodies both the Incredible Hulk and The Thing. He wears green pants and has purple skin - an opposite to the Hulk's purple pants and green skin. His favorite television show is TV Puppet Pals. He is voiced by Frank Welker.
- White Tiger: A White Tiger who has cat-like powers. He can not speak in English, instead he speaks in cat noises.
- Sam R I: A samurai that is skilled in katana wielding and sword-play, he has the standard superhuman attributes
- Living Bullet: A bullet man who is very fast and can move very quickly.
- Phan Tone: A ghostly superhero who goes through everything so no villains can attack him.
- Rat Man: A superhero in a rat costume. He drives around in the Ratmobile and attacks villains with Ratarangs. He is also a repairman on the side.
- Tiki Torch: A flaming tiki-like Justice Friend with the power of flight and pyrokinesis
- Miss Spell: The only female member of The Justice Friends, she is much like Scarlet Witch in the Marvel comics
- Monkey: Dexter's lab monkey who is the superhero secret identity that he is unaware of. He also stars in his own separate segment of the show called Dial M for Monkey.
- Capital G: A superhero who has the ability to grow really big and shrink really small. He's mostly modelled after the Harlem Globetrotters
- Snowman: A snowman superhero with ice and snow powers. He is lazy and usually doesn't use them.
- Global Security Commander: He is the commander who is in charge of giving out orders to the team
- Agent Honeydew: She is Monkey's sidekick and girlfriend; she is currently working as a federal agent
- Fatboy: He Major Glory's sidekick after Dee-Dee had turned the Major's offer in the Dex Labs Episodes
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- Mushu Gai Man: