An assault gun is a type of self-propelled artillery which uses an infantry support gun mounted on a motorized chassis, normally an armored fighting vehicle, which are designed to provide direct fire support for infantry attacks, especially against other infantry or fortified positions. Assault guns were pioneered by the Soviet Union and Nazi Germany during the 1930s, initially being self-propelled guns with direct fire in mind, with Germany introducing the first purpose-built assault gun, the Sturmgeschütz III, in 1940.

Self-propelled artillery is artillery equipped with its own propulsion system to move toward its firing position. Within the terminology are the self-propelled gun, self-propelled howitzer, self-propelled mortar, and self-propelled rocket artillery. They are high mobility vehicles, usually based on continuous tracks carrying either a large field gun, howitzer, mortar, or some form of rocket/missile launcher. They are usually used for long-range indirect bombardment support on the battlefield.