A dune buggy is a recreational vehicle with large wheels, and wide tires, designed for use on sand dunes or beaches. The design is usually a modified vehicle with a modified engine mounted on an open chassis. The modifications usually attempt to increase the power to weight ratio by either lightening the vehicle or increasing engine power or both.

They are also often referred to as air buggies, and those with an open frame chassis are called sandrails.

A similar, more recent generation of off road vehicle, often similar in appearance to a sand rail but designed for different use, is the "off road go kart". The difference between a dune buggy or go kart and an "off road" buggy or kart is sometimes nothing more than the type of tires fitted -sand tires or all terrain tires - but "off road" go karts and buggies are a rapidly developing category of their own.

Initially dune buggies were designed for navigating desert or beaches (hence the word "dune"). However, dune buggies have become more diversified in terms of the terrain they can handle and are being built for more generic off road tasks, such as CORR / SCORE indoor track racing. Some are even built for and used as on-road vehicles. Typically the function is determined before the buggy is created in order to maximize the comfort or abilities of the vehicle.

Although dune buggies can be bought (as a kit), many drivers make their own. This is done by separately buying chassis, engine, tires, steering wheel, and axles. Some builders make their own chassis, which creates a special, customized vehicle.