The Kliment Voroshilov (KV) tanks are a series of Soviet heavy tanks named after the Soviet defence commissar and politician Kliment Voroshilov who operated with the Red Army during World War II. The KV tanks were known for their heavy armour protection during the early stages of the war, especially during the first year of the German invasion of the Soviet Union. In certain situations, even a single KV-1 or KV-2 supported by infantry could halt German formations. The German Wehrmacht at that time rarely deployed its tanks against KVs, as their own armament was too poor to deal with the "Russischer Koloss" – "Russian Colossus".

This article deals with the history and development of tanks of the Soviet Union and its successor state, the Russian Federation; from their first use after World War I, into the interwar period, during World War II, the Cold War and modern era.