The Red Army is the name given to the Armed Forces of the Soviet Union after the disintegration of the Tsarist forces in 1917. "Red" referred to the shed blood of the working class. The Workers' and Peasants' Red Army (Raboche-Kriestianskaya Krasnaya Armia) was created by a decree of the Council of People's Commissars in 1918 from the already-existing Red Guard. Leon Trotsky, the Soviet Union's commissar for war from 1918 to 1924 is often regarded as its founder. At its height during World War II, the Red Army numbered over 11 million officers and enlisted soldiers. After its victory over Nazi Germany the numbers were reduced to approximately 3 million.

In 1946 the word 'Red' was removed from the name of the Soviet armed forces.

See Red Army Faction for the German and Japanese Red Army for the Japanese terrorist group and People's Liberation Army for the Chinese Red Army.