The Reliant Regal is a small three-wheeled car and van that was manufactured from 1952 to 1973 by the Reliant Motor Company in Tamworth, England, replacing the earlier Reliant Regent three-wheeled cyclecar van which had its origins in a design bought by Reliant from the Raleigh Bicycle Company. As a three-wheeled vehicle having a lightweight construction, under UK law it is considered a "tricycle" and can be driven on a full motorcycle licence. In 1962, with the release of the Reliant Regal 3/25, van and estate versions with a side-hinged rear door were marketed as the Reliant Supervan.

A three-wheeler is a vehicle with three wheels. Some are motorized tricycles, which may be legally classed as motorcycles, while others are tricycles without a motor, some of which are human-powered vehicles and animal-powered vehicles.