Flyball is a dog sport in which teams of dogs race against each other from a start/finish line, over a line of hurdles , to a box that releases a tennis ball to be caught when the dog presses the spring loaded pad, then back to their handlers while carrying the ball.

Flyball is run in teams of four dogs, as a relay.The course consists of four hurdles placed 10 feet (3 m) apart from each other, with the starting line six feet (1.8 m) from the first hurdle, and the flyball box 15 feet (4.5 m) after the last one, making for a 51-foot (15.5 m) length. The hurdle height is determined by the shoulder height of the smallest dog in the team. Each dog must return its ball all the way across the start line before the next dog crosses. Ideal running is nose-to-nose at the start line. The first team to have all four dogs cross the finish line error free wins the heat. Penalties are applied to teams if the ball is dropped or if the next relay dog is released early.

Flyball provides an entertaining and active way to interact with one's dog and other dog lovers in an environment that is fun and allows the dogs exercise and enjoyment. It is especially a great way to burn off the energy of dogs with a high drive to work, such as Boarder Collies and Terriers.

A great part of flyball's popularity stems from the fact that it is one of the competition activities available tomixed breed of dogs, allowing rescued mutts to shine along side their purebred canine friends. Though Boarder Collies currently dominate the courses, many champion teams have Cross Breeds on them.

Also, flyball is not limited to the size of the breed, as smaller dogs such as Parson Russell Terriers and Whippets often compete with great success in mixed-breed teams (teams consisting of dogs of various sizes and breeds). Smaller dogs are often prized as the hurdle height is based on the height of the smallest dog in the team. Their only limitation is whether they can trigger the release pad, and small dogs often have to fully jump on it to do so.

Flyball is one of the non-hunting dog sports in which dogs and people work as a team. Many casual pet owners use their flyball time more as a way to relax and socialize with other dog owners than as a competition, and many champion flyball dogs are essentially pet dogs with a hobby, rather than dedicated sporting or working dogs.