The ZU-23 mounts twin 23-mm cannons on a towed two-wheel carriage. The cannons are positioned side-by-side between large ring-type trunnions. In appearance, the ZU-23 can be confused with the 14.5-mm ZPU-2; however, the shape and placement of the ZU-23 ammunition boxes (at right angles to the gun carriage) and prominent muzzle flash suppressors are distinguishing features.

A battalion of 18 ZU-23s was organic to the Soviet airborne division and is the division's principal AAA weapon. It has an effective AA range of 2,500 meters. It also can be used effectively against lightly armored ground vehicles. In firing position, the ZU-23 is leveled by jacks and stabilized on a three-point base. An optical-mechanical computing sight is used for anti-aircraft fire and a straight-tube telescope for ground targets.

Ammunition is fed from box magazines mounted on the outside of each trunnion. Reloading is fast and uncomplicated. The magazines are easily accessible and the beginning link of the new belt attaches to the link of the last old cartridge which automatically interrupts the firing cycle when it reaches the feedway and signals the bolt to remain open.