The 12th Army was part of the Red Army forces during the Russian Civil War. It operated along three fronts and it existed under two formations. Initially, the 12th was formed in 1918 and was assigned to the Astrakhan region and Northern Caucasus. The unit was demobilized in March 1919. It was then reorganized (once again as the 12th Army) in June 1919, and it continued to serve on the Western Front. Later, it was assigned to the Southwestern Front (principally in Kiev) during the summer of 1920. The reorganized 12th was demobilized in December 1920.