The Kalmyk Autonomous Soviet Socialist Republic (Russian: Калмыцкая Автономная Советская Социалистическая Республика; Kalmyk: Хальмг Автономн Советск Социалистическ Республик, romanized: Xaľmg Avtonomn Sovetsk Socialistiçesk Respublik, [xalʲmək aftɐˈnomnə sɐˈvʲɛt͡sk sɐt͡sialʲɪsˈtit͡ʃəsk rʲɪsˈpublʲɪk]) was an autonomous republic of the Russian SFSR that existed at two periods of time. Its administrative center was Elista.

The Kalmyk ASSR was first established when the Kalmyk Autonomous Oblast (established 4 November 1920) had its status increased on 22 October 1935. On 27 December 1943 in conjunction with the deportation of over 93,000 Kalmyks to various locations in Central Asia and Siberia, the Kalmyk ASSR was abolished and its territory was split between adjacent Astrakhan, Rostov and Stalingrad Oblasts and Stavropol Krai. Soviet authorities renamed the former republic's towns and villages.

The Kalmyk ASSR was re-established when the newly formed Kalmyk Autonomous Oblast (re-established following the rehabilitation of the Kalmyks in January 1957) had its status increased on 29 July 1958. On 18 October 1990, the declaration of the sovereignty and transformation of Kalmykia into a Soviet Socialist Republic by the Kalmyk Supreme Soviet was accepted by the Congress of People's Deputies of the Russian SFSR on 24 May 1991. It existed until 31 March 1992, when its status was changed to a republic within the Russian Federation.

A minor planet, 2287 Kalmykia, discovered in 1977 by Soviet astronomer Nikolai Stepanovich Chernykh, is named after the Kalmyk ASSR.