The T-26 tank was a Soviet light infantry tank used during many conflicts of the 1930s as well as during World War II. It was a development of the British Vickers 6-Ton tank and is widely considered one of the most successful tank designs of the 1930s.

It was produced in greater numbers than any other tank of the period, with more than 11,000 manufactured. During the 1930s, the USSR developed a record amount of 53 variants of the T-26, including different combat vehicles based on its chassis (flame-throwing tanks, combat engineer vehicles, remotely controlled tanks, self-propelled guns, artillery tractors, armoured carriers). Twenty-three of these were series-produced, others were experimental models.

Though nearly obsolete by the beginning of World War II, the T-26 was the most important tank of the Spanish Civil War and played a significant role during the Battle of Lake Khasan in 1938 as well as in the Winter War in 1939–40. The T-26 was the most numerous tank in the Red Army's armored force during the German invasion of the Soviet Union in June 1941. The Soviet T-26 light tanks last saw use in August 1945, during the Soviet invasion of Manchuria.