The SU-85 was a Soviet self-propelled gun used during World War II, based on the chassis of the T-34 medium tank. Earlier Soviet self-propelled guns were meant to serve as either assault guns, such as the SU-122, or as mobile anti-tank weapons; the SU-85 fell into the latter category. The designation SU-85 is derived as follows: ‘SU’ stands for the Russian: Samokhodnaya Ustanovka – self-propelled carriage, while “85” signifies the bore of the vehicle’s armament, the 85mm D-5T gun.

There were two versions: the basic SU-85 had a fixed commander’s cupola with a rotating periscope and three vision blocks; the improved SU-85M had the same casemate as the SU-100, with a commander’s cupola as used on the T-34-85.