Serbian diaspora refers to the Serbian communities that have formed outside Serbia and autochthonous areas of Western Balkans. Existence of a numerous Serbian diaspora are mainly consequences of either economic or political (coercion or expulsions) reasons.
There are over 2 million Serbs in diaspora throughout the world, although some sources put that figure as high as 4 million. The largest community is found in German-speaking countries (Germany, Austria and Switzerland) amounting in total to more than 1.2 million. The largest overseas community is reported from the United States, with more than 1 million members.
First wave of Serb emigration took place since the end of 19th century and lasted until the World War II and was caused by economic reasons; particularly large numbers of Serbs (mainly from peripheral ethnical areas such as Herzegovina, Montenegro, and Lika) emigrated to the United States.
Second wave took place after the end of the World War II. At this time, members of royalist Chetniks and other political opponents of communist regime fled the country mainly going overseas (United States and Australia) and, to a lesser degree, United Kingdom.
Third, and by far the largest wave, was economic emigration started in the 1960s when several Western European countries signed billateral agreements with then-Yugoslavia allowing the recruitment of workers from Yugoslavia to work in the industrial sector of those countries, and lasted until the end of the 1980s. Main destinations for Serbian emigrants were West Germany, Austria, and Switzerland, and to a lesser extent France and Sweden. That generation of Serbian diaspora is collectively known as gastarbajteri (after German word "Gastarbeiter" meaning guest-worker, since the most of the emigrants headed for German-speaking countries).
Most recent emigration took place during the 1990s, and was caused by both political and economic reasons. Political reasons were dominant cause for Serbs from Croatia and Bosnia and Herzegovina since there were war raging in the first half of the 1990s. On the other side, for Serbs from Serbia main reasons for emigrating was economic collapse which Serbia experienced during that decade caused by the UN economic sanctions imposed on the country. It is estimated that 300,000 people left Serbia during that period, 20% of which had a higher education.
700469544000000000069,544 (2011) Serbian ancestry 
55,114 (0.3%) English and Serbian-speakers (2011 census); 9,857 only Serbian-speakers; the 2006 census recorded 95,362 people of Serbian ancestry. There is estimations of 300,000 Serbs in Australia.
^"Srbi u Austriji traže status nacionalne manjine". Blic. 2010-10-02. "Srba u Austriji ima oko 300.000, po brojnosti su drugi odmah iza Austrijanaca i više ih je od Slovenaca, Mađara i Gradištanskih Hrvata zajedno, koji po državnom ugovoru iz 1955. godine imaju status nacionalne manjine u Austriji", navodi se u saopštenju.
^"So, just how many Serbs live in Britain? Britić figures defy census figures of 2001.". Ebritic.com. June 3, 2011. There have been various attempts to estimate the population of Serbs living in the UK. The simplest answer was the 2001 national census which stated that there are 31,244 UK residents born in Serbian and Montenegro. A further 6,992 were born in Croatia. However, the obvious problems are that many Serbs were born in the UK (maybe even most British Serbs). Moreover, in 2001 there were still a large number of Kosovan Albanians in Britain who of course would have been registered as being born in Serbia and Montenegro.
^"Ethnic group". 2013 census (Statistics New Zealand). Includes all people who stated each ethnic group, whether as their only ethnic group or as one of several. Where a person reported more than one ethnic group, they were counted in each applicable group.