The Armenian diaspora is a term used to describe the communities of Armenians living outside of Armenia and Nagorno-Karabakh. Of the total Armenian population living worldwide (in 2004 estimated to be 9,000,000), only about 3,000,000 live in Armenia and about 130,000 in Nagorno-Karabakh. The Armenian diaspora population is estimated to be 8,000,000. (See chart of population breakdown by country below). Only one-fifth of the world's Armenian population lives in the former Soviet republic of Armenia, and their pre-World War I homeland until the 1920s once covered five or six times that of present-day Armenia, including the eastern regions of Turkey, parts of Iran and Syria. Although an Armenian diaspora existed since the Armenian loss of statehood in 1375 (when the Armenian Kingdom of Cilicia fell to the Mamelukes), it grew in size only after the Armenian Genocide. Although many Armenians perished, others managed to escape, and established themselves in various Eastern European, Balkan, and Middle Eastern cities, such as Moscow, Russia; Sochi, Russia; Odessa, Ukraine; Sevastopol, Crimea (Ukraine); Tbilisi, Georgia; Batumi, Georgia; Plovdiv, Bulgaria; Athens, Greece; Beirut, Lebanon; and Aleppo, Syria. Israel has a sizable Armenian community centered on the Armenian Quarter in Jerusalem.

Several million Armenians settled in Western Europe (i.e. France, Germany, Italy and the Netherlands) and in the Americas (North and South) as early as in the 1890s. Substantial Armenian communities also exist in the Russian Far East as well as in the former Soviet republics of Central Asia. Some of these groups were encouraged to settle in the area by both Tsarist and Soviet authorities while others had no choice but to come, being part of Stalin's population deportations. Armenian communities can also be found in India, Australia, New Zealand, Sub-Saharan Africa (Sudan, South Africa, and Ethiopia), and as far east as Singapore, Myanmar and Hong Kong. Armenian exile communities even once thrived in China, Japan and the Philippines, but the status of Armenian culture in these countries has all but disappeared.

Immediately after the Armenian Genocide, the Armenians of the diaspora lived in refugee camps. However, as their financial situation improved, the camps grew into towns, and these towns became cities. This was the case of many of the Armenian-populated regions in Lebanon like Anjar and Bourj Hammoud. In time, the Armenians organized themselves by building churches, schools, community centers, etc. Various political parties and benevolent unions, such as the Armenian Revolutionary Federation (ARF or Dashnaktsutiun), the Social-Democrat Hunchakian party (Hunchak), and the Armenian General Benevolent Union (AGBU), were established wherever there was a considerable number of Armenians.

In the 1940s and 1950s, the Soviet Union was trying to extend its influence throughout the world, and especially in the Middle East. The Social-Democrat Henchagian party, being ideologically close to communism, supported the Soviet Union in its struggle to expand in the Middle East. Partisans of the AGBU, supposedly being politically neutral, also supported the Soviet Union, because Armenia was part of Soviet Union. The ARF, despite its socialist background was a nationalistic party, objected, as it propagated the idea of a free, independent, and united Armenia. As the ARF struggled to preserve the flag, coat of arms, and national anthem of the Independent Armenian Republic of 1918-1922, others chose to support Soviet Armenia, seeing it as the only place in the world where Armenians could live safely as Armenians.

There was also a conflict between the leaders of the Armenian Apostolic Church. Armenians had 2 Catholicoses. One of them was located in Echmiadzin, Armenia and was supported by the Soviet KGB, the Hunchaks, and the Ramgavars, while the other was located in Antelias, Lebanon and was supported by the Dashnaks, as they thought that the Catholicosate of Echmiadzin was a tool for propagation of communism. In the 1950s, during the climax of this conflict, there were armed clashes between partisans of the 2 "sides", and also assassination attempts, acts of desecration, etc. However, tensions eased out in 1975 during the Lebanese Civil War, when Armenians had to stick together in order to overcome opposing forces. And unfortunately, some Armenians fought for Iraq in the army under Saddam Hussein in the 1980s Iran-Iraq war, two countries known to have large Armenian communities until the 2000s.

Following the expansion of Pan-Arabism in Egypt and Syria, Islamism in Iran, and the Lebanese Civil War, tens of thousands of Armenians emigrated from the Middle East and established themselves in the United States, Canada, France, and elsewhere, where they founded lobbies to support the Republic of Armenia and extend the international recognition and condemnation of the Armenian Genocide. Today, the countries with the largest number of Armenians (excluding Armenia and Nagorno-Karabakh) in rank of order are Russia, United States, France, Iran (although the community shrunk in size since the 1970s), Lebanon, Georgia (republic), Syria, Argentina, Canada, and Ukraine.