The country's Constitutional Court has ruled that the "Moldovan" language will be replaced by Romanian as the former Soviet republic's official tongue.
Moldova's 1991 Declaration of Independence stated that Romanian was the new country's language, but the Constitution of 1994 changed that to "Moldovan."
Constitutional Court Chairman Alexandru Tanase ruled on December 5 that the Declaration of Independence takes precedence over the Constitution.
Moldova's communist opposition has criticized the decision.
Moldova was part of Romania until 1940, when it was annexed by the Soviet Union, which renamed the region's language "Moldovan."
Romanian President Traian Basescu called the Constitutional Court's ruling "an act of justice."
The decision comes a day after U.S. Secretary of State John Kerry paid a short visit to Moldova.
Last week Moldova's pro-European government initialed an Association Agreement with the European Union.
On December 1, for the first time, Moldovan President Nicolae Timofti attended Romania's National Day festivities marking the country's unification in 1918.