A right of return clause was included in the 1991 constitution for persons who left Lithuania after the Soviet occupation in 1940 and their descendants.

In 1989, the legislature passed a nationality act granting automatic citizenship to those persons who could establish their own birth, or that of a parent or grandparent, within Lithuanian borders.

[1] Subsequent applicants for citizenship were required to meet a set of naturalization standards, including Lithuanian language testing.

This is commonly attributed to a relatively low level of immigration from other areas of the Soviet Union, especially Russia, resulting in a more ethnically homogenous population.

[2] In November 2006, the Constitutional Court of the Republic of Lithuania ruled that the Law on Citizenship (wording of 17 September 2002 with subsequent amendments and supplements) was "controversial, inconsistent and confusing".

The most notable member of this diaspora was Lithuanian President Valdas Adamkus, who had become a United States citizen; he formally renounced US citizenship before taking the oath of office.

Dual citizenship can also be extended to descendants of Lithuanian citizens who were exiled to Siberia and stayed in Soviet Union countries.

President Dalia Grybauskaitė vetoed it, stating that "according to the Constitution, dual citizenship is a rare exception, not a common case.

In 2018, at the request of Lithuanian parliament, the constitutional court clarified that being a citizen of both Lithuania and another state at the same time is not acceptable.

[19] As a result, the Lithuanian nationality allows for freedom of movement in any of the states of the EU / EEA / EFTA / Switzerland.

The QNI considers, in addition to travel freedom, on internal factors such as peace & stability, economic strength, and human development as well.