AC Cars Group Ltd. formerly known as Auto Carriers Ltd. is a British specialist automobile manufacturer and one of the oldest independent car marques founded in Britain. Since 2009 company was renamed AC Cars by Gullwing GmbH and has headquarters in Germany.

The first automobile from what would eventually become AC was presented at the Crystal Palace motor show in 1903; it was a 20 HP touring car and was displayed under the Weller name. The Weller Brothers of West Norwood, London, planned to produce an advanced 20 hp (15 kW) car. However, their financial backer and business manager John Portwine, a butcher, thought the car would be too expensive to produce and encouraged Weller to design and produce a little delivery three-wheeler. Weller did so, called it the Auto-Carrier, and a new company was founded and named Autocars and Accessories; production started in 1904. The vehicle caught on quickly and was a financial success. In 1907 a passenger version appeared, called the A.C. Sociable. It had a seat in place of the cargo box.

An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor. Most definitions of the term specify that automobiles are designed to run primarily on roads, to have seating for one to eight people, to typically have four wheels, and to be constructed principally for the transport of people rather than goods.

The term motorcar has also been used in the context of electrified rail systems to denote a car which functions as a small locomotive but also provides space for passengers and baggage. These locomotive cars were often used on suburban routes by both interurban and intercity railroad systems.

There are approximately 600 million passenger cars worldwide (roughly one car per eleven people). Around the world, there were about 806 million cars and light trucks on the road in 2007; the engines of these burn over a billion cubic meters (260 billion US gallons) of petrol/gasoline and diesel fuel yearly. The numbers are increasing rapidly, especially in China and India.