Kart racing (as the word is so spelled by enthusiasts) or karting is a variant of open-wheeler motor sport with simple, small four-wheeled vehicles called karts, go-karts, or gearbox/shifter karts depending on the design. By definition a kart must have no suspension (relying on chassis flex), and no differential (solid back axle). They are usually raced on scaled-down tracks, but are sometimes driven as entertainment or as a hobby by non-professionals. Karting is commonly perceived as the stepping stone to the higher and more expensive ranks of motorsports. Karts were initially created in the United States in the 1950s post-war period by airmen as a way to pass spare time. Art Ingels is generally accepted to be the father of karting. He built the first kart in Southern California in 1956. Karting has rapidly spread to other countries, and it currently has a large following in Europe.

Kart racing is usually used as a low-cost and relatively safe way to introduce drivers to motor racing. Many people associate it with young drivers, but adults are also very active in karting. Karting is considered the first step in any serious racer's career. It can prepare the driver for high-speed wheel-to-wheel racing by helping develop quick reflexes, precision car control, and decision-making skills. In addition, it brings an awareness of the various parameters that can be altered to try to improve the competitiveness of the kart (examples being tire pressure, gearing, seat position, chassis stiffness) that also exist in other forms of motor racing.

As well as "serious" competitive kart racing, many commercial enterprises offer casual hire of karts. Such karts are usually powered by small, detuned four-stroke engines and are far slower than the fully-fledged competitive versions.

Many, perhaps most Formula One racers grew up racing karts, most prominent among them Michael Schumacher, Ayrton Senna and Mika Häkkinen. Many NASCAR drivers also got their start in racing from karts, such as Darrell Waltrip, Lake Speed, Ricky Rudd, Tony Stewart, and Kyle Petty.

A popular video game rendition is the Mario Kart series. Also, many childrens' video game racing titles (i.e. Crash Team Racing and Konami Krazy Racers) feature karts as the main vehicles.