The 5th Mechanised Corps was a mechanised corps of the Red Army, formed on three occasions. It was first formed in 1934 and was converted into the 15th Tank Corps in 1938. It was reformed in the Far East in 1940 and moved west before the German invasion of the Soviet Union. It fought in the First Battle of Smolensk, losing large numbers of tanks in the Lepel counterattack. The corps was encircled in the Smolensk pocket and after breaking out was disbanded in late August 1941. Its third formation, from elements of the 22nd Tank Corps, occurred in September 1942. The corps fought in: Operation Little Saturn, Operation Gallop, the Second Battle of Smolensk, the Dnieper–Carpathian Offensive, and the Second Jassy–Kishinev Offensive. In September 1944, it became the 9th Guards Mechanised Corps.

The first Battle of Smolensk was a battle during the second phase of Operation Barbarossa, the Axis invasion of the Soviet Union, in World War II. It was fought around the city of Smolensk between 10 July and 10 September 1941, about 400 km (250 mi) west of Moscow. The Ostheer had advanced 500 km (310 mi) into the USSR in the 18 days after the invasion on 22 June 1941.