The ISU-122 (Самоходная установка на базе танка ИС с орудием калибра 122мм, ИСУ-122) is a Soviet assault gun used primarily in anti-tank tasks during World War II. Unlike the ISU-152, the ISU-122 was primarily utilised for anti-armour missions with its 122 mm A-19 field gun, whereas the ISU-152 was used more for indirect fire support and anti-fortification operations with its devastating 152 mm ML-20S howitzer. Following the beginning of the Korean War, the Soviet Union committed to providing military assistance to China. In September 1950, China received 10 infantry division tank regiments from the Soviet Union, comprising 300 T-34-85 medium tanks, 60 IS-2 heavy tanks, and 40 ISU-122 self-propelled artillery, as well as trucks and other support vehicles. More than 2,000 military vehicles were sent to China, along with three large and medium-sized repair factories and various ammunition.

Introduced in Update 1.91 "Night Vision", the ISU-122 is well-armoured and mounted with a 122 mm A-19 field gun. It has greater shell penetration and a slightly faster reload speed than the earlier ISU-152. On the right roof corner, a DShK heavy machine gun provides adequate deterrence against incoming aircraft and lightly armoured vehicles. As both the 152 mm and 122 mm guns are installed on the same chassis, which was also utilised for the IS-2 heavy tank, other characteristics remain the same.