Advisory opinion on Kosovo's declaration of independence in the context of "Resolution 1244"

A declaration of independence is an change by a nation in a defined territory that it is independent and constitutes a state. Such places are usually declared from part or all of the territory of another state or failed state, or are breakaway territories from within the larger state. In 2010, the UN's International Court of Justice ruled in an advisory opinion in Kosovo that "International law contains no prohibition on declarations of independence", though the state from which the territory wishes to secede may regard the declaration as rebellion, which may lead to a war of independence or a constitutional settlement to resolve the crisis.

The 2008 Kosovo declaration of independence, which proclaimed the Republic of Kosovo to be an independent and sovereign state, was adopted at a meeting held on 17 February 2008 by 109 out of the 120 members of the Assembly of Kosovo, including the Prime Minister of Kosovo, Hashim Thaçi, and by the President of Kosovo, Fatmir Sejdiu (who was not a member of the Assembly). It was the second declaration of independence by Kosovo's Albanian-majority political institutions; the first was proclaimed on 7 September 1990.

The legality of the declaration has been disputed. Serbia sought international validation and support for its stance that the declaration was illegal, and in October 2008 requested an advisory opinion from the International Court of Justice. The Court determined that the declaration did not violate international law.