The Mongolia Garrison Army (駐蒙軍, Chūmōgun) was an army of the Imperial Japanese Army during World War II.

The Japanese Mongolia Garrison Army was raised on December 27, 1937, as a garrison force in Japanese-dominated Inner Mongolia and adjacent areas of north China. From July 4, 1938, the Mongolia Garrison Army came under the administrative jurisdiction of the North China Area Army. In January 1939 the Cavalry Group was added, consisting of the 1st Cavalry Brigade and 4th Cavalry Brigade. In December 1942, the 4th Cavalry Brigade was sent to the Twelfth Army and the remainder of the Cavalry Group was converted into the 3rd Tank Division.

During most of the Second Sino-Japanese War and due to the Soviet–Japanese Neutrality Pact, Inner Mongolia was largely a backwater region, and the Mongolia Garrison Army, with its antiquated horse cavalry functioned largely to assist and train the Mengjiang National Army and Mongolian Cavalry Corps. It was thus unprepared for the massive Soviet Red Army armored assault at the end of World War II. The Mongolia Garrison Army was officially disbanded on July 27, 1946. Many of its survivors became Japanese prisoners of war in the Soviet Union.

• List of Armies of the Japanese Army

• Frank, Richard B (1999). Downfall: The End of the Imperial Japanese Empire. New York: Random House. ISBN 0-679-41424-X.
• Jowett, Bernard (1999). The Japanese Army 1931-45 (Volume 2, 1942-45). Osprey Publishing. ISBN 1-84176-354-3.
• Madej, Victor (1981). Japanese Armed Forces Order of Battle, 1937-1945. Game Publishing Company. ASIN: B000L4CYWW.

• Wendel, Marcus. "Axis History Factbook". Japanese Mongolia Garrison Army.