Kosovo Serbs gather to mark the anniversary of the 1389 Battle of Kosovo at Gazimestan, near the capital Pristina June 28, 2013 (Photo: Reuters)
Croatia becomes the European Union's 28th member on Monday, the second ex-Yugoslav republic to join the bloc after Slovenia.
Six other countries of the Western Balkans, with a joint population of almost 19 million, are unlikely to join the bloc before the end this decade, as the fallout from Yugoslavia's violent collapse in the 1990s as well as corruption and sluggish economic growth continue to slow their progress.
Following are summaries of each country's prospects:
Hardline communism under dictator Enver Hoxha collapsed in Albania in 1991, and the country of 3 million people joined NATO in 2009. Progress towards EU membership has been dogged by concerns over democracy, organised crime and corruption.
Albania applied for EU candidate status in April 2009 but has twice been turned down, though it was granted visa-free travel to countries in the EU's so-called Schengen zone in 2010. Brussels has cited shortcomings in the functioning of democratic institutions such as the parliament and judiciary.
Bosnia has yet to apply for EU membership. Since its 1992-95 war, the 3.8 million-strong country has been split into two autonomous regions, overseen by an international envoy and a loose and weak central government.
Bosnia's progress remains hamstrung by rivalry between its Serb, Croat and Muslim communities, whose political leaders have failed to implement constitutional reforms mandated by the European Union and the European Court of Human Rights.
Visa-free travel to the Schengen zone began in 2010 but reforms remain stymied up by the political impasse.
Europe's youngest country with a population of 1.8 million ultimately hopes to join the EU. It declared independence from Serbia in 2008 and has so far been recognised by 100 countries. However, only 22 of the EU's 27 members have recognised it.
It continues to be patrolled by NATO peacekeepers and, since 2008, by an EU police and justice mission, more than a decade after NATO bombed Serbia and took control of Kosovo.
Organised crime, endemic corruption and continued tensions between the Albanian majority and Serb minority have deterred investors and held back development.
Kosovo's parliament this month ratified a landmark EU-brokered agreement in which Serbia ceded de facto control over predominantly Serb-populated northern Kosovo, in exchange for progress towards accession talks. Brussels has recommended opening talks for a stability and association agreement, the first step towards membership.
Macedonia is a candidate for membership of both NATO and the EU but progress has been hostage to a long-running dispute with its southern neighbour Greece. Athens objects to its use of the name "Macedonia", saying it implies territorial ambitions towards Greece's northern province of the same name.
The Macedonian government meanwhile has begun pursuing an overtly nationalist agenda which diplomats say has further antagonised Greece and the EU.
The EU granted the Adriatic country of 700,000 people candidate status in 2010 and opened accession talks last year. Montenegro closed the second negotiating chapter in April but issues such as the judiciary and corruption have yet to be discussed.
Brussels has stressed Podgorica must do more to clamp down on organised crime and corruption. Montenegro, which dissolved its state union with Serbia in 2006, unilaterally adopted the euro as its official currency in 2002.
The biggest market in the Western Balkans with a population of 7.3 million is due to start EU membership talks by January.
Serbia unblocked its EU integration in April, when its socialist-nationalist government signed an EU-brokered deal with Kosovo, agreeing to cede the control over northern Kosovo that it had retained even after its former province declared independence in 2008.
Brussels has said recognition of Kosovo is not a precondition for membership but stressed the two countries must normalise relations.