The Speedway Under-21 World Championship is an annual speedway event held each year organized by the International Motorcycling Federation (FIM) since 1977.

Motorcycle speedway, usually referred to simply as speedway, is a motorcycle sport involving four and sometimes up to six riders competing over four anti-clockwise laps of an oval circuit. The motorcycles are specialist machines that use only one gear and have no brakes. Racing takes place on a flat oval track usually consisting of dirt, loosely packed shale, or crushed rock. Competitors use this surface to slide their machines sideways, powersliding or broadsiding into the bends. On the straight sections of the track, the motorcycles reach speeds of up to 70 miles per hour (110 km/h).