The Uzbek Soviet Socialist Republic (US: /ʊzˈbɛkɪstæn, -stɑːn/ ^ⓘ, UK: /ʊzˌbɛkɪˈstɑːn, ʌz-, -ˈstæn/), also known as Soviet Uzbekistan, the Uzbek SSR, UzSSR, or simply Uzbekistan and rarely Uzbekia, was a union republic of the Soviet Union. It was governed by the Uzbek branch of the Communist Party of the Soviet Union, the legal political party, from 1925 until 1990. From 1990 to 1991, it was a sovereign part of the Soviet Union with its own legislation.

Beginning 20 June 1990, the Uzbek SSR adopted the Declaration of State Sovereignty within its borders. Islam Karimov became the republic's inaugural president.

On 31 August 1991, the Uzbek SSR was renamed the Republic of Uzbekistan and declared independence three months before the Soviet Union's dissolution on 26 December 1991.

Uzbekistan was bordered by Kazakhstan to the north; Tajikistan to the southeast; Kirghizia to the northeast; Afghanistan to the south; and Turkmenistan to the southwest.

The name, Uzbekistan, literally means "Home of the Free", taken from an amalgamation of uz (Turkic: "self"), bek (Turkic: "master"), and -stan (Persian: "land of"). However, the official name of the republic was the Uzbek Soviet Socialist Republic as defined by its 1937 and 1978 Constitutions.

In 1924, the borders of political units in Central Asia were changed along ethnic lines determined by Vladimir Lenin's Commissar for Nationalities, Joseph Stalin. The Turkestan ASSR, the Bukharan People's Soviet Republic, and the Khorezm People's Soviet Republic were abolished and their territories were eventually divided into five separate Soviet Socialist Republics, one of which was the Uzbek Socialist Soviet Republic, created on 27 October 1924. The next year Uzbekistan became one of the republics of the Union of Soviet Socialist Republics (Soviet Union). In 1928, the collectivization of land into state farms was initiated, which lasted until the late 1930s.

Uzbekistan included the Tajik ASSR until 1929, when the Tajik ASSR was upgraded to an equal status. In 1930, the Uzbek SSR capital was relocated from Samarkand to Tashkent, which remained the capital since. In 1936, Uzbekistan was enlarged with the addition of the Karakalpak ASSR taken from the Kazakh SSR in the last stages of the national delimitation in the Soviet Union. That same year in December, it was renamed to the Uzbek Soviet Socialist Republic. Further bits and pieces of territory were transferred several times between Kazakhstan and Uzbekistan after World War II.

In 1937–38, during the Great Purge, a number of alleged nationalists were executed, including Faizullah Khojaev, the first prime minister.