The Light Tank M24 was an American light tank used during World War II and in postwar conflicts including the Korean War and with the French in the War in Algeria and First Indochina War. In British service it was given the service name Chaffee, after the United States Army General Adna R. Chaffee, Jr., who helped develop the use of tanks in the United States armed forces.

Combat experience indicated several shortcomings of the Light Tank M3/M5, the most important of them being weak armament. The T7 design, which was initially seen as a replacement, evolved into a mediocre Medium Tank M7 and was eventually rejected in March 1943, which prompted the Ordnance Committee to issue a specification for a new light tank, with the same powertrain as the M5A1 but armed with a 75 mm gun.

In April 1943 the Ordnance Corps together with Cadillac division of General Motors started work on the new project, designated Light Tank T24. Every effort was made to keep the weight of the vehicle under 20 tons. The armor was kept light, with the glacis plate only 25 mm thick (but sloped at 60 degrees from the vertical). A new lightweight 75 mm gun was developed, a derivative of the gun used in the B-25H Mitchell bomber. The gun had the same ballistics as the M3, but used a thinly walled barrel and different recoil mechanism. The design also featured wider (16 inch) tracks and torsion bar suspension. It had a relatively low silhouette and a three-man turret.