Because of the restrictions that only the infantry could use tanks, the US. Cavalry looked for possibilities to get tanks as well. In 1931 General Douglas MacArthur talked the Army into the use of 'Combat Cars' for the cavalry ('tanks' would be exclusive for the infantry). Around 1934-35 a couple of experimental light tanks were produced, the T2, T2E1 and the T2E2. This would lead for the cavalry to the T5. The T5 was further developed into the T5E2, that became the M1 Combat Car (are you still with me?) The M1 had a 7 cylinder Continental W670 radial engine. The turret had a .50 and a .30 inch caliber machinegun. There was an additional .30 at the front of the hull.

The next version, the M2 had improved maneuverability. In July, 1940 a new Armored Force was founded and the development went from then hand in hand between the infantry and the cavalry, and the 'Combat Cars' were from then on 'tanks'. The M1 and the M2 became the M1A1 and the M1A2. These light tanks saw never action, but were important in training crews and further development. Main engine for the M2A2E3 and the M2A3E3 became the Guiberson diesel engine which gave the vehicle a greater radius.

The last of the M2 series, the M2A4 got a 37mm canon in the turret. An order for 329 tanks was given to the American Car Foundry in October, 1939. The first was delivered in April, 1940. The order was extended to 365 vehicles, the last was delivered in March, 1941. The M2A4 was deployed in the Pacific Ocean, but was mainly used as trainer vehicle.

The Light Tank M3 was a further development of the concept M1 and had still the Continental W670 as engine. The armor became thicker. To compensate the weight, the suspension had to be built stronger. The older version had still 'gunports' in the turret, in the M3 these were abandoned. In March, 1941, the M3 went into production again at the American Car Foundry. During the production adjustments were made, such as a whole welded turret instead of the riveted one. This was a great step forward in reducing the weight without losing armor thickness. Half way 1941 the canon got a stabilizer.

The British Army used the M3 in North Africa under the name 'Stuart' Mk I. They made some important adjustments, such as the additional fuel tanks that could be jettisoned, larger fenders and smokepots on the turret. The name 'Stuart', used by the Brits, was not the only one,… crews named her affectionately 'Honey'. The American crews had no special name for her, other than abusive ones because of the cramped space in the vehicle.

There were 5811 M3's produced until January 1943. Of these, 1834 went to the British army who deployed the little tank mostly in Africa. The Soviet Union's Red Army got 1336 M3's. Because of the demand of the aircraft industry for the Continental engines, 1285 M3's were delivered with the Guiberson T1020 diesel engine.

A important improvement led to the M3A1. The turret was completely redeveloped. It lost the extra cupola and could rotate electrically. The new turret got an internal basket for the crew to sit in. In the previous models, the crew, loader and gunner, had to 'walk' with the turret when it was in motion and had to step over the crankshaft housing.

Until the introduction of the turret basket, it was common to maneuver the complete tank in the direction of fire. But not every crew was happy with the 'basket', the space was more cramped and often the crew removed it.

Later models of the M3A1 lost the two extra machineguns sideways in the hull, that were remotely operated by the driver in the M2A4 and the M3. They were of limited use and the Brits had removed them mostly already in the predecessors. From the 4621 M3A1 built, 1594 went to the British and 1676 went to the Soviet Union. A total of 4410 M3A1's had the Continetal and 211 had the Guiberson diesel engine.