The AMX-40 was a French prototype main battle tank.

In the early 1980s came the next in the GIAT manufactured, export-driven AMX series. As the AMX-32 had failed to attract any potential sales, the company decided to produce yet another upgrade. This was the AMX-40 Main Battle Tank. The development of the AMX-40 began in 1980 as a clean sheet design. In 1983 the first prototype was finished and presented at the Satory Exhibition of that year. Two further prototypes were produced in 1984; the last, fourth, was fabricated in 1985. The design was not intended for service in France, but as a successor to the AMX-32, the improved export version of the AMX-30. However the efforts to obtain foreign orders failed, the most serious potential customer to have considered the design being Spain. In 1990 it was no longer offered for export.

The tank was of fairly standard configuration, with the driver at the front, the turret in the center, housing a gunner, commander and loader, and the engine at the rear. Its armament consisted of a 120 millimetre calibre smoothbore gun, with an optionally coaxial 20 millimetre calibre F2 autocannon. The fire control system was the COTAC also used for the AMX 30 B2. As its dimensions were rather small: 6.8 metres (22 ft 4 in) long, 3.36 m (11 ft 0 in) wide and 2.38 m (7 ft 10 in) high at the turret roof, the ammunition load was limited to just 35 rounds. The tank was powered by a 1,100 horsepower (820 kW) Poyaud V12X diesel engine coupled to an automatic ZF transmission. The number of road wheels per side was increased from five to six, compared to the AMX-32.