A road train is a trucking concept used in remote areas of Australia to move bulky loads efficiently. A road train consists of a relatively conventional prime mover, but instead of pulling one trailer or semi-trailer, the road train pulls two or more of them.

Australia has the largest and heaviest road-legal vehicles in the world, with some configurations topping out at close to 200 tonnes. The majority are between 80 and 120 tonnes. Two-trailer road trains, or "doubles" are allowed in rural areas of all Australian states except Victoria and Tasmania, and in two capital cities - Adelaide in South Australia, and Perth in Western Australia. Three trailer road trains (triples) operate in western New South Wales, western Queensland, South Australia, Western Australia and the Northern Territory, with the last three states also allowing AB-Quads (3.5 trailers). Darwin, NT, is the only capital city in the world that will allow triples and quads to within 1 km of the central business district

Road trains are used for transporting all manner of materials, with livestock, fuel, mineral ores and general freight the most common. Their cost-effective transport has played a significant part in the economic development of remote areas, with some communities totally reliant on a regular service.

Overtaking a road train can be quite difficult. Patience, assistance from the driver, and large amounts of clear road are required. Many road train drivers help by blinking their right-turn indicators a couple of times to indicate that the road ahead is clear.