- Model 1940 (German designation: T-34/76A) - This was a production model built in 1940, armed with a L-11 76.2 mm tank gun; it had a welded or cast two-man turret. Due to a shortage of new V-2 diesel engines, the initial production run from the Gorky factory was equipped with the BT tank's MT-17 gasoline-powered engine and an inferior transmission and clutch (Zheltov 2001:40–42).
- Model 1941 (T-34/76B) - This production model was built in 1941, with a heavier armor, a cast or welded two-man turret, and the superior F-34tank gun.
- Model 1942 (T-34/76C) - This was a production model built in 1942, with increased armor protection and many simplified components. It had new 'waffle' tracks, new wheel patterns, a new driver's hatch and a round transmission access cover. Some had the headlight moved to the left side of the hull. Most were equipped with cast two-man turrets although a few welded ones remained.
- Model 1943 (T-34/76D, E, and F) - This production model was built from May 1942 to 1944, with a cast or pressed hexagonal turret. It was nicknamed "Mickey Mouse" by the Germans because of its appearance with the twin round turret roof hatches open. Official Soviet military designation was Model 1942. Turrets manufactured in different factories had minor variations, sometimes called "hard-edge", "soft-edge", and "laminate" turrets, but in military service these details did not warrant different designations.
- Earlier production is sometimes called Model 1942/43, and was designated T-34/76D by German intelligence.
- Later production variants had a new commander's cupola. This variant was referred to as T-34/76E by the Germans.
- Turrets produced at Uralmash in Sverdlovsk (Yekaterinburg) had a distinctive rounded appearance because they were made in a special forge. Tanks produced with these turrets there and at Chelyabinsk were called T-34/76F by the Germans.
- T-34/57 - A very small number of T-34s were fitted with the ZiS-4 L/73 high-velocity 57 mm gun in 1941 and 1943 to be used as tank destroyers. This gun had better penetration than the 76.2 mm F-34 (140 mm of steel at 500 m, as opposed to 90 mm), but the small HE projectile was inadequate for use against unarmored targets.
- OT-34 - This was a T-34 flame-thrower tank fitted with an internally mounted flamethrower replacing the hull machine-gun. Usually it was a modified Model 1941 with the ATO-41 flamethrower or Model 1942 with ATO-42.
- T-34M - This unit was a prototype (A-43) with improved armor, hexagonal three-man turret, torsion bar suspension, sprung road wheels, and increased fuel and ammunition storage. Five hulls were built, but development was abandoned when the war broke out.
- Model 1943 - This production model was built from February to March 1944 at Zavod 112, with the 85 mm D-5T gun and a new larger cast three-man turret, a commander's cupola and two dome-shaped ventilators clustered together on top of the turret.
- Model 1944 - This was a production model built from March 1944 to the end of 1944, with the simpler 85 mm ZiS-S-53 gun. The radio was moved from the hull into the turret and the commander's cupola was moved rearward. There was an improved layout and a new gunner's sight.
- Model 1945 - This was a production model built in 1944-45, with an electrically powered turret traverse motor, an enlarged commander's cupola with a one-piece hatch, squared front fenders, and the TDP (tankovoy dimoviy pribor) smoke system with electrically detonated MDSh canisters.
- OT-34-85 (sometimes called TO-34) - This was a T-34-85 flamethrower tank, with the ATO-42 in place of the bow machine gun.
- T-34-100 - example armed with a prototype 100mm LB-1 cannon.
- T34 Concrete Armour
- SU-85 was a T-34-based tank destroyer armed with an 85 mm D-5T gun.
- SU-100 was a T-34-based tank destroyer armed with a 100 mm D-10S gun.
- SU-122 - This unit was a T-34 based self-propelled howitzer armed with a 122 mm M-30S howitzer.
- PT-34 - This was a mine roller tank, mostly built on the T-34 Model 1942 or T-34-85 chassis.
- T-34-T (T after T-34- stands for tyagach ["tractor"]) - During World War II, some old, battle damaged T-34 medium tanks were rebuilt as armored recovery vehicles (ARVs) with their turret removed; sometimes the turret ring was plated over or a superstructure was added in place of the turret. They were used solely for towing operations. It is also known under designation TT34.
- SPK-5 (1955) - This was a turretless T-34 fitted with a crane with a capacity of 10 tons on a rotatable mount fitted in the turret ring.
- SPK-5/10M - An SPK-5 was fitted with electro-hydraulic controls for the crane.
- T-34-TO (1958) (TO after the T-34- stands for technicheskoye obsuzhivaniye ["technical maintenance"]) - This variant was a technical maintenance vehicle fitted with an extensive array of tools and a work platform over the engine deck.
- T-34-85 turrets were built into a bunker to create a fixed piece.
- T-34 tanks were converted into tracked firefighting vehicles used to fight oil fires. Two engines from MiG-21 were fitted to an overlapping mount on the turret ring.
- Flakpanzer T-34 - This German conversion was a single T-34 made into a self-propelled antiaircraft gun armed with a 2 cm Flakvierling 38 in a new armored turret with an open top. The single vehicle manufactured was used by PzJagAbt 653 in July 1944.