The Assault Tank T14 was a cooperative project between the U.S. Army and the British Army to develop a universal infantry tank. The Assault Tank T14 project was never completed because the prototype was not sent to the UK until 1944, by which time the Churchill infantry tanks had been in service for two years and had substantially improved from their initial prototype. The Medium Tank T20 is the result of U.S. efforts to develop a similarly armoured tank with a higher speed for use other than infantry support. Only two prototypes were produced, one for testing in the U.S. and the other for testing in Britain. The tank transported to Britain is still on display at the tank museum in Bovington. The British had built the Heavy Assault Tank A33 "Excelsior" design to the same specifications as the Assault Tank T14, but it was never deployed.

Introduced in Update 1.67 "Assault", the Assault Tank T14 is designed to break through powerful enemy defences. Its 75 mm M3 tank gun reloads quickly, and its armour is strong enough to withstand numerous hits. With its primitive vertical stabilizer, it can also fire while moving and make fast stops around corners to attack the opponent. Its front armour is greatly slanted at 61°. Side-top armour is also sloped at 30°, and since it is the same thickness as the front, it is easy to angle without fear of revealing weak points. The lower side armour is not sloped, although it is thicker than the top and front to guard against glancing shots. Players will be delighted to experience this special heavy tank and lead the charge during battles.