The Act of Reinstating Independence of Lithuania (Lithuanian: Lietuvos Valstybs atkrimo aktas) or Act of 16 February was signed by the Council of Lithuania on 16 February 1918, proclaiming the restoration of an independent State of Lithuania, governed by democratic principles, with Vilnius as its capital. The Act was signed by all twenty representatives of the Council, which was chaired by Jonas Basanaviius. The Act of 16 February was the result of a series of resolutions on the issue, including one issued by the Vilnius Conference and the Act of 8 January. The path to the Act was long and complex because the German Empire exerted pressure on the Council to form an alliance. The Council had to carefully maneuver between the Germans, whose troops were present in Lithuania, and the demands of the Lithuanian people.

The immediate effects of the announcement of Lithuania's re-establishment of independence were limited. Publication of the Act was prohibited by the German authorities, and the text was distributed and printed illegally. The work of the Council was hindered, and Germans remained in control over Lithuania. The situation changed only when Germany lost World War I in the fall of 1918. In November 1918 the first Cabinet of Lithuania was formed, and the Council of Lithuania gained control over the territory of Lithuania. Independent Lithuania, although it would soon be battling the Wars of Independence, became a reality.

The laconic Act is the legal basis for the existence of modern Lithuania, both during the interwar period and since 1990. The Act formulated the basic constitutional principles that were and still are followed by all Constitutions of Lithuania. The Act itself was a key element in the foundation of Lithuania's re-establishment of independence in 1990. Lithuania, breaking away from the Soviet Union, stressed that it was simply re-establishing the independent state that existed between the world wars and that the Act never lost its legal power.

The Council of Lithuania (Lithuanian: Lietuvos Taryba, German: Litauischer Staatsrat, Polish: Rada Litewska), after July 11, 1918 the State Council of Lithuania (Lithuanian: Lietuvos Valstybės Taryba) was convened at the Vilnius Conference that took place between 18 and 23 September 1917. The twenty men who composed the council at first were of different ages, social status, professions, and political affiliations. The council was granted the executive authority of the Lithuanian people and was entrusted to establish an independent Lithuanian state. On 16 February 1918, the members of the council signed the Act of Independence of Lithuania and declared Lithuania an independent state based on democratic principles. 16 February is celebrated as Lithuania's State Restoration Day. The council managed to establish the proclamation of independence despite the presence of German troops in the country until the autumn of 1918. By the spring of 1919, the council had almost doubled in size. The council continued its efforts until the Constituent Assembly of Lithuania (Lithuanian: Steigiamasis Seimas) first met on 15 May 1920.