The 1991 Soviet coup d'tat attempt, also known as the August Coup, was a failed attempt by hardliners of the Soviet Union's Communist Party to forcibly seize control of the country from Mikhail Gorbachev, who was Soviet President and General Secretary of the Communist Party at the time. The coup leaders consisted of top military and civilian officials, including Vice President Gennady Yanayev, who together formed the State Committee on the State of Emergency (GKChP). They opposed Gorbachev's reform program, were angry at the loss of control over Eastern European states and fearful of the USSR's New Union Treaty which was on the verge of being signed. The treaty was to decentralize much of the central Soviet government's power and distribute it among its fifteen republics.

The GKChP hardliners dispatched KGB agents, who detained Gorbachev at his holiday estate but failed to detain the recently elected president of a newly reconstituted Russia, Boris Yeltsin, who had been both an ally and critic of Gorbachev. The GKChP was poorly organized and met with effective resistance by both Yeltsin and a civilian campaign of anti-Communist protestors, mainly in Moscow. The coup collapsed in two days, and Gorbachev returned to office while the plotters all lost their posts. Yeltsin subsequently became the dominant leader and Gorbachev lost much of his influence. The failed coup led to both the immediate collapse of the Communist Party of the Soviet Union (CPSU) and the dissolution of the USSR four months later.

Following the capitulation of the GKChP, popularly referred to as the "Gang of Eight", both the Supreme Court of the Russian Soviet Federative Socialist Republic (RSFSR) and President Gorbachev described its actions as a coup attempt.

The dissolution of the Soviet Union (1988–1991) was the process of internal political, economic, and ethno-separatist disintegration within the USSR, which resulted in the end of its existence as a sovereign state. Being its ultimate unintended aftermath, it brought an end to General Secretary (later also President) Mikhail Gorbachev's effort to reform the Soviet political and economic system in an attempt to stop a period of political stalemate and economic backslide, known as the "Era of Stagnation" or simply as "Zastoy" (Russian for "stagnation" or "stasis"). In late 1991, amidst the catastrophic political crisis and several republics already breaking off the Union, the leaders of three of its founding members (the fourth one being dissolved in the 1930s) declared that the Soviet Union no longer existed, eight more republics joined their declaration shortly thereafter. Gorbachev had to resign and what was left of the parliament to formally acknowledge the collapse as a fait accompli.

The process began with growing unrest in the Union's various constituent national republics developing into an incessant political and legislative conflict between them and the central government. Estonia was the first Soviet republic to declare state sovereignty inside the Union on November 16, 1988. Lithuania was the first republic to declare independence from the Soviet Union by the Act of March 11, 1990 (not counting the autonomy of Nakhchivan, which had declared independence from both the Soviet Union and the Azerbaijan SSR a few weeks earlier, later rejoining Azerbaijan), with its Baltic neighbours and the Southern Caucasus republic of Georgia joining it in a course of two months.

The failure of the 1991 August Coup, when communist hardliners and military elites tried to overthrow Gorbachev and stop the failing reforms, led to the government in Moscow losing most of its influence, and many republics proclaiming independence in the following days and months. The secession of the Baltic states was recognized in September 1991. The Belovezh Accords were arbitrarily signed on December 8 by President Boris Yeltsin of Russia, President Kravchuk of Ukraine, and Chairman Shushkevich of Belarus, recognising each other's independence and creating the Commonwealth of Independent States (CIS) instead of the Soviet Union. Kazakhstan was the last nation to leave the Union, proclaiming independence on December 16. All the ex-Soviet republics, with the exception of Georgia and the Baltics, joined the CIS on December 21, signing the Alma-Ata Protocol.On December 25, Gorbachev resigned and turned over his presidential powers—including control of the nuclear launch codes—to Yeltsin, who was now the first president of the Russian Federation. That evening at 7:32 p.m., the Soviet red banner was lowered from the Kremlin for the last time and replaced with the Russian tricolour flag. The following day, the Declaration 142-Н of the Supreme Soviet's only functioning upper chamber, the Soviet of the Republics, recognised self-governing independence for the former Soviet republics, formally dissolving the Union. Both the Revolutions of 1989 in the Eastern Bloc and the dissolution of the Soviet Union marked the end of the Cold War.

In the aftermath of the Cold War, several of the former Soviet republics have retained close links with Russia and formed multilateral organizations such as CSTO, the CIS, the Eurasian Economic Community, the Union State, the Eurasian Customs Union, and the Eurasian Economic Union, for economic and military cooperation. On the other hand, the Baltic states and most of the former Warsaw Pact states became part of the European Union and joined NATO, while some of the other former Soviet republics like Ukraine, Georgia and Moldova have been publicly expressing interest in following the same path since the 1990s.