The MT-LB (Mnogotselevoy Tyagach Legky Bronirovanny) is a multipurpose tracked armored vehicle that has been used for a wide variety of roles including an APC (its primary role), artillery prime mover, command vehicle, reconnaissance vehicle, ambulance, and anti-tank missile platform. The MT-LB is based on the chassis of the PT-76 light amphibious tank and like its predecessor, is fully amphibious and features all-welded steel armor. The crew compartment is located at the front, with the engine behind it, and a troop compartment at the rear with twin rear-facing doors; the driver position is also provided with a periscope. The basic APC version features a small turret for a single 7.62-mm machine gun although firing ports are provided in the troop compartment. Amphibious propulsion is provided by the tracks, and the vehicle features full NBC protection. As an APC, the MT-LB can carry up to 11 troops, but the basic model can be configured to carry up to 2 tons of cargo, or tow weapons as heavy as 6.5 tons. Overall, more than 80 variants of the MT-LB were produced for both the Soviet as well as other Warsaw Pact countries which included domestic production in Bulgaria and Poland; incredibly, it was also license-produced by Sweden. Thousands remain in service around the world (including Russia), a testament to the soundness, reliability, and versatility of the design.

The basic MT-LB entered service sometime in the early 1960s, and serves as APC, artillery tractor (sometimes known as the MT-LB-T), and armored ambulance. A version with wider tracks is known as the MT-LBV for use in snow or swamps, of which the MT-LB M1989 features a higher caliber (12.7-mm gun). The MTP-LB is a repair vehicle and can be distinguished by the lack of a turret. Engineer variants include the ADZM as well as the MT-LB M1980. Some have also been equipped with the SNAR-10 'Big Fred' battlefield surveillance radar, while the K-611 and K-612 are radiological reconnaissance vehicles. Armed variants include those equipped with the 2B9 Vasilek mortar, 9K114 Shturm ATGM, 9K35 Strela-10 SAM, and ZU-23-2 anti-aircraft gun. A major development of the ML-LB design resulted in the MT-LBu armored command and reconnaissance vehicle (ACRV). This is used to operate alongside 2S1 and 2S3 self-propelled artillery vehicles. Artillery support variants include the 1V13 battery fire direction center, 1V14/1V15 battery command vehicle, and 1V16 battalion fire direction center. Non-artillery variants include the 1V21 air defense command vehicles, MT-LBus jamming vehicle, KDKhR-1N NBC recon vehicle, Taran series of electornic warfare systems, as well as radar vehicles for the Zoopark-1 and 'Dog Ear' radars.