| Middle School Students (seasons 1 - 3)|
High School Students (season 4)
| Middleton Middle School (seasons 1 - 3)|
Middleton High School (season 4)
| James Possible (father)|
Ann Possible (mother)
Kim Possible (sister)
"Nana" Possible (grandmother)
Slim Possible (uncle)
Joss Possible (cousin)
| Ron Stoppable|
|No Known Love Interests|
|No Known Pets|
|No Known Nemesis|
|Behind the Scenes|
|Shaun Fleming (seasons 1 - 3)|
Spencer Fox (season 4)
Jim and Tim Possible are identical twin brothers, and younger siblings of Kim Possible, whom she calls "Tweebs"–a portmanteau of "twin" and "dweebs". They are distinguished by the major coloring of their clothing; Tim habitually wears red, while Jim wears green.
When they are not harassing Kim, they are making trouble with their scientific experiments and inventions such as launching rockets or sending out screensavers of an unsuspecting Kim to all of Middleton.
Jim and Tim were never far from each other and exhibited a high level of synchronization. Antagonistic, anarchic and brilliant, they cared little for rules and restrictions on their activities, and rebelled against their older sister's attempts to rein them in. They invented twin-speak slang between themselves, with their trademark catch-phrases being "Hicka-bicka-boo?" and "Hoo-sha!" in response.
Despite their notably high intelligence, Jim and Tim were still typically immature in certain areas. Perhaps the best example of this was their idolizing Adrena Lynn, a famed but false stuntwoman. The twins failed to recognize that Lynn was not actually performing her own stunts, and that attempting to copy her stunts could and eventually did get them hurt. Furthermore, the twins lacked the proper equipment that even Lynn would have used to stage a convincing stunt. Worst of all, their attempt occurred after Lynn had been exposed as a fake, but because her show was the only one they bothered to watch, the twins had missed all the news reports that would have shown them the truth.
The twins were born sometime during Kim's pre-K year. Kim had been hoping for a baby sister, but her mom pointed out that the baby might be a boy, and her dad jokingly suggested it might be twins.
Even at the tender age of ten, the twins constructed an array of amazing and often destructive devices, typically using parts made available by their father's experiments, or simply taking and breaking down various appliances from Kim's room. Though Kim generally resented them doing so, the twins occasionally contributed to her missions, and even managed to save her a few times. When Dr. Drakken stole a neuro-compliance chip and used it on Kim to make her his mind-controlled servant, it was thanks to the twins' invention of a handheld silicon phase disruptor that Kim was returned to normal.
Jim and Tim were nuisances at home, constantly chasing after their experiments run wild, or getting caught red-handed before they could do something questionable or potentially destructive. Despite the obvious headaches they cause their parents, the twins' creativity was never entirely stifled, only momentarily contained long enough for the latest mess to be cleaned up. Though James was annoyed when they borrowed his work materials without asking, he still displayed pride over their collective creative genius. Ann was always concerned with keeping the twins from damaging the house, and often ordered them to take whatever they were doing outside.
- Main article: Kim Possible
The twins greatly enjoy being regular headaches for Kim, but they did assist her with missions on occasion. After they entered high school, they became entirely responsible for the regular maintenance on Kim's car, the Sloth.
Ron Stoppable and Rufus
Jim and Tim regularly spent time watching TV with Ron Stoppable and Rufus.
- Main article: Wade
Wade considered the twins his intellectual peers and sometimes collaborated with them.
- Main article: Bonnie Rockwaller
Jim and Tim briefly socialized with Bonnie Rockwaller, though on both sides this was mostly to momentarily antagonize Kim, and not an actual friendship. The twins later repaired Bonnie's car after it was destroyed, but once she broke their contract, they undid their labor and left her stranded.
Bonnie did suggest that the twins become the new Middleton High School mascots after Ron could no longer continue his duties, and while this was again mostly to annoy Kim, it was actually a good fit and could arguably be considered one of the few genuinely nice things that Bonnie did for anyone.
Jim and Tim were mechanical and scientific prodigies. They spent the bulk of their time inventing, obtaining parts by breaking down household appliances or "borrowing" their father's work materials. While many of these inventions exploded, ran wild, or were halted in progress by others, a number of them reached completion and proved far more effective than those designed by older, more experienced scientists. The twins displayed a preference for regularly practicing in their father's field of rocket science, but also had considerable talent in automobile repair, despite no known formal training in either area. Their intelligence was high enough that they consistently proved smarter than children their age, students above their age, and even adults far beyond their age.
- silicon phase disruptor
- remote-operated containment field
- molecular transducer/smoothie maker
- Jimunicator and Timunicator
- grappling beam
- modified Lorwardian disintegration beam unit, in collaboration with Ron Reiger
- The boys can be told apart by their major color scheme. Jim wears green, while Tim wears red.
- Their voice was originally provided by Shaun Fleming who is known for playing Leonard Helperman in Teacher's Pet. Since their redesign, it has been provided by Spencer Fox who is best known for voicing Dash Parr in the Pixar movie The Incredibles.
- Their age is given in October 31st when they state that they are 10.
- In the German version they are called "Zwombies", a portmanteau of "Zwillinge" (twins) and Zombies.
- The tweebs helped Kim on 6 missions, not counting their missions as adults in "A Sitch in Time":
- Stopping Drakken from trying to mind control everyone in the world with micro-chips on their foreheads.
- Helping Kim find Ron when he was lost with Dr. Drakken at the North Pole.
- Getting Ray-X back and stopping Hank Perkins from keeping it in Drakken's liar.
- Fixing up her car to help stop Motor Ed and Shego when they were riding the Kepler at high speed, with shock waves causing massive chaos in the Middleton neighborhood.
- Helping her find out Camille Leon was a suspect in fashion crimes.
- Helping her turn Ron back to normal when he mutated into a giant, fifteen-feet tall, junk-food eating, mutant/monster.
- The first half was when they were younger before they went to MHS with Kim, and the other half to where they were older and in High School with Kim.