The Troublemakers are a group of antagonists from Season Four. They made their debut in the episode The Boy with the Dragon Skateboard. Their only goals in life are to cause havoc, chaos, and make big trouble in Umi City. They have a secret weapon called the Trouble Ray which fulfills their malicious troublemaking ways, and a vehicle they call the Trouble Truck which they use to get away. They live in outer space in their TroubleMakers' Space Station shaped like a rhombus. They are some of the main villains in Team Umizoomi.
Little Trouble is shorter and wider. He wears purple glasses and orange gloves. His orange hair is styled into a mohawk. He also speaks in an English accent. His uniform has long pant legs.
The Troublemakers both have light lavender skin, pointy ears, and yellow and purple uniforms.
Big Trouble is taller and thinner. He wears purple ski goggles and blue gloves. His blue hair stands up. He speaks in a voice that makes him sounds dim-witted. Big Trouble is sometimes called "Old Chap" by Little Trouble.
Trouble Truck, the Troublemakers' getaway vehicle, is gray with blue lines over the tires. He also releases a large cloud of gasoline. His focus is not above average as he sometimes crashes into certain things, like a big mud puddle or a trash can.
The Troublemakers nearly have the same personality: They like to cause chaos in Umi City, make trouble, and bother Team Umizoomi. However, Little Trouble acts smarter and stuck-up while Big Trouble is slightly dim-witted. When their plans go wrong, they both tend to blame each other usually.
It is currently unknown why they like to cause chaos, and if they'll turn good like most, if not all, of the other bad guys did.
The Troublemakers both have the power to cause trouble with a powerful weapon known as the Trouble Ray. The gadget is used mostly to cause trouble (hence the name) and almost stop Team Umizoomi. It was used to destroy a boy's dragon skateboard and make all fifty baby penguins at the zoo got scattered all over Umi City. But the one power the Troublemakers don't have that Team Umizoomi has is true cooperation. Big Trouble and Little Trouble argue about which one gets the blame, but neither give in so easily.
- They are similar to Wario and Waluigi from the Mario series, as they both like to cause trouble and mischief like them. Also both are rivals to the main protagonists. Their colour schemes (yellow and purple) are similar as well.
- The Troublemakers never appeared with DoorMouse until Umi Grand Prix!.
- They are never encountered and/or engaged with DoorMouse.
- The list of Season Four episodes that the Troublemakers don't appear in is:
Head to (The Troublemakers/Gallery).