A Demolition Derby is a type of motorsport event popularised in the United States, in which drivers of old vehicles race against one another in an open arena - the objective of the game being to smash and destroy and ultimately immobilise the oppostition, until only one vehicle is left, which is deemed the winner.

Usually the race is conducted in a seemingly unstructured fashion - that is to say competitors can drive in any direction around the arena. This makes a demolition derby distinct from banger racing (popular in Europe), in which vehicles compete around a conventional one-way racetrack and the race is won in terms of the first car to the chequered flag.

Although demolition derby vehicles are normally scrap automobiles, they can be conducted with almost any powered wheeled vehicle - bizarre versions of the sport using combine harvesters and lawn mowers have been practiced in various parts of the world.