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.

A motorized tricycle, motor trike, or motortrycle is a three-wheeled vehicle based on the same technology as a bicycle or motorcycle, and powered by an electric motor, motorcycle, scooter or car engine.