The BTR-40 is an early Cold War era armored personnel carrier of Soviet origin. It was developed shortly after World War 2 and is based on the GAZ-63 utility vehicle. The BTR-40 was one of the first mass produced armored personnel carriers. It was supplemented and replaced by the BTR-152 and BTR-60 since the 1960's. The BRDM-1 reconnaissance vehicle was derived from the BTR-40.

The BTR-40 is based on the GAZ-63 4x4 utility vehicle. If features a thin steel monocoque hull. The cabin and crew compartment are connected. Most versions have an open roof. Firing ports are located on either side and one, two or three pintle mounts are provided.

Often the BTR-40 was fitted with only a single 7.62mm SGMB machine gun. Up to three weapons can be fitted. Occasionally a 12.7mm DShKM or 14.5mm KPVT heavy machine gun are fitted. The BTR-40A anti-aircraft version features a ZTPU-2 mount with two 14.5mm KPVT heavy machine guns.

The welded steel armor protects the crew from small arms fire and shell splinters. Most BTR-40 feature and open roof. The gunners are exposed when operating the pintle mounts. NBC protection and smoke grenade launchers are not provided.

The 4x4 chassis with large wheels make the BTR-40 highly manueverable on road. Cross country mobility is good in all but the most diffcult terrain. The 80 hp petrol engine provides a maximum speed of 80 km/h. The BTR-40 is not amphibious, unlike the BRDM-1 reconnaissance vehicle that was derived from the BTR-40.

The BTR-40 was used in large quantities with Soviet forces. It was eventually replaced by the larger BTR-152. Many have been exported to Soviet allies around the world. China used both Soviet and locally produced vehicles under the designation Type 55. A limited number of BTR-40's remain in service with third world nations today.