The Karabakh movement (Armenian: Ղարաբաղյան շարժում "Gharapaghyan sharjhum"), also known as the Artsakh movement (Armenian: Արցախյան շարժում), was a national liberation movement in Armenia and Nagorno-Karabakh from 1988 to 1991 that advocated for the reunification of the Nagorno-Karabakh Autonomous Oblast (NKAO) – an autonomous enclave within Soviet Azerbaijan – with Soviet Armenia. The movement was motivated by fears of cultural and physical erasure under government policies from Azerbaijan. Throughout the Soviet period, Azerbaijani authorities implemented policies aimed at suppressing Armenian culture and diluting the Armenian majority in Nagorno-Karabakh through various means, including border manipulations, encouraging the exodus of Armenians, and settling Azerbaijanis in the region. In the 1960s, 1970s, and 1980s, Armenians protested against Azerbaijan's cultural and economic marginalization The concept of reunification (“Miatsum”) was so deeply embedded among Armenians in Nagorno-Karabakh that the region was almost universally regarded as an integral part of Armenia rather than a distinct entity.

Armenians had petitioned Soviet authorities to transfer the mostly Armenian-populated Nagorno-Karabakh Autonomous Oblast (NKAO) in Azerbaijan to Armenia. By 1988, nearly one million Armenians from several regions of the republic engaged in regular demonstrations, centered on Yerevan's Theater Square (today Freedom Square).

The Karabakh Committee, a group of ethnic Armenian intellectuals from Armenia along with the Karabakh-based local group "Krunk", led the movement. After 1989, the movement transformed into the Pan-Armenian National Movement (HHSh) and won majority in the 1990 parliamentary election. In 1991, both Armenia and Nagorno-Karabakh declared independence from the Soviet Union. A referendum in 1988 was held to transfer the region to Soviet Armenia, citing self-determination laws in the Soviet constitution. This act was met with a series of pogroms against Armenians across Azerbaijan, and in November 1991, the Azerbaijani government passed a motion aimed at abolishing the autonomy of the NKAO and prohibiting the use of Armenian placenames in the region. Initially, the movement relied on non-violent means, including petitions, marches, vigils, hunger strikes, demonstrations, and general strikes, and was met with anti-Armenian violence. By 1992, the conflict had escalated into the First Nagorno-Karabakh War.

Up until the 2018 Armenian Revolution, the Karabakh Movement was the largest mass movement in Armenian history. It was also the largest instance of public mobilization in the Soviet Union since its formative years in the 1920s. At one point in the movement, up to a million protestors were mobilized in Yerevan.

Azerbaijan's inability to suppress the Karabakh Movement has significantly influenced Azeri nationalism, which is widely considered institutionally anti-Armenian.

During the Soviet Era, the Armenians of Nakhichevan and of Lachin were subjected to gradual ethnic cleansing by Soviet Azeri authorities resulting in the exodus of all Armenians from the region. During the Soviet Era, Armenians were scapegoated for state, societal and economic shortcomings in Azerbaijan. The Karabakh Movement is characterized as a struggle for national liberation by both Armenians and others. The concept of reunification (“Miatsum”) was so deeply embedded among Armenians in Nagorno-Karabakh that the region was almost universally regarded as an integral part of Armenia rather than a distinct entity. Nagorno-Karabakh was unique in the Soviet Union as the only autonomous region whose ethnic majority matched that of a neighboring republic (Armenia) but was not allowed to join it.

Building on these grievances, Armenian intellectuals within the Karabakh Movement also rejected the long-standing belief that Armenia’s membership of the USSR was necessary for protection against Turkey. Up until Armenia's incorporation into the Soviet Union, the Republic of Turkey and its Ottoman predecessor had aimed at eliminating Armenia and transforming it into a Turkish protectorate or vassal state. Led by figures such as Levon Ter-Petrosyan and Vazgen Manukyan, Armenian intellectuals aimed for complete independence and the possibility of peaceful coexistence with neighboring states, marking a fundamental shift in Armenian political thought.

Although the Karabakh Movement came to a flashpoint in 1988, its origins date back to the 1920s, during which it was suppressed by the Soviet authorities. For decades, an underground movement in Nagorno-Karabakh sought unification with Armenia. During periods of political easing or major change in the USSR—such as in 1945, 1965, and 1977—Armenians submitted letters and petitions to Moscow requesting that Nagorno-Karabakh be transferred to Soviet Armenia.