The Mountain Autonomous Soviet Socialist Republic (Russian: Горская Автономная Советская Социалистическая Республика, romanized: Gorskaya Avtonomnaya Sovetskaya Sotsialisticheskaya Respublika; Chechen: Лаьмнийн Автономин Советийн Социалистийн Республика, romanized: Lämniyn Avtonomin Sovetiyn Socialistiyn Respublika) or Mountain ASSR (Russian: Го́рская АССР, romanized: Górskaya ASSR) was a short-lived autonomous republic within the Russian SFSR in the Northern Caucasus that existed from 20 January 1921, to 7 July 1924.

The Mountainous Republic of the Northern Caucasus was created from parts of the Kuban and Terek Oblasts by the indigenous nationalities after the Russian Revolution; however, Soviet rule was installed on this territory after the Red Army conquered the Northern Caucasus in the course of the Russian Civil War, and the former republic was transformed into a Soviet one.

The Sunzha Cossack Okrug and the city of Vladikavkaz were directly subordinated to the VTsIK until 17 October 1924, when North Caucasus Krai was formed and integrated all of the former ASSR in addition to those two units.

[3] During the Cold War, many Western historians saw the disintegration of the Mountaineer Republic as a divide-and-conquer strategy by the Soviet government to keep the peoples of the Caucasus weak and subjugated to Moscow.

[4] 1918–24  Turkestan3 1918–41  Volga German4 1919–90  Bashkir 1920–25  Kirghiz2 1920–90  Tatar 1921–91  Adjarian 1921–45  Crimean 1921–91  Dagestan 1921–24  Mountain 1921–90  Nakhichevan 1922–91  Yakut 1923–90  Buryat1 1923–40  Karelian 1924–40  Moldavian 1924–29  Tajik 1925–92  Chuvash5 1925–36  Kazakh2 1926–36  Kirghiz 1931–92  Abkhaz 1932–92  Karakalpak 1934–90  Mordovian 1934–90  Udmurt6 1935–43  Kalmyk 1936–44  Checheno-Ingush 1936–44  Kabardino-Balkarian 1936–90  Komi 1936–90  Mari 1936–90  North Ossetian 1944–57  Kabardin 1956–91  Karelian 1957–92  Checheno-Ingush 1957–91  Kabardino-Balkarian 1958–90  Kalmyk 1961–92  Tuvan 1990–91  Gorno-Altai 1991–92  Crimean