Assault gun

Assault gun
Top left: German WWII Stug III assault guns in Finnish service.
Top right: US WWII M4A3 (105) assault gun.
Lower left: Swedish Cold War Ikv 91 assault gun.
Lower right: Japanese Type 16 maneuver combat vehicle (Japanese: 16式機動戦闘車) modern assault gun.

An assault gun (from German: Sturmgeschütz, lit.'storm gun', meaning "assault gun") is a type of armored infantry support vehicle and self-propelled artillery, mounting an infantry support gun on a protected self-propelled chassis, intended for providing infantry with heavy direct fire support during engagement, especially against other infantry or fortified positions, secondarily also giving some armored protection and anti-armor capability.

Assault guns were pioneered by the Soviet Union and Nazi Germany during the 1930s, initially being self-propelled guns with direct fire in mind (such as the Soviet SU-5-1), with Germany introducing the first purpose-built (and purpose-named) assault gun, the Sturmgeschütz III, in 1940.