The Independent State of Croatia (Serbo-Croatian: Nezavisna Država Hrvatska, Независна Држава Хрватска, NDH; German: Unabhängiger Staat Kroatien; Italian: Stato Indipendente di Croazia), often referred to simply by the abbreviation NDH, was a World War II puppet state of Germany and Italy, which was established in parts of Axis-occupied Yugoslavia. The NDH was founded on 10 April 1941, after the invasion of Yugoslavia by the Axis powers. The NDH consisted of most of modern-day Croatia and Bosnia and Herzegovina, together with some parts of modern-day Serbia. The regime targeted Serbs, Jews, Muslims and Roma people, as part of a large-scale genocide campaign in places such as the Jasenovac concentration camp.
In its judgement in the Hostages Case, the Nuremberg Military Tribunal concluded that NDH was not a sovereign state. According to the Tribunal, "Croatia was at all times here involved an occupied country".
The state was officially a monarchy since the signing of the Laws of the Crown of Zvonimir on 15 March 1941 and an Italian protectorate from the signing of the Treaties of Rome on 18 May 1941 until the Italian capitulation on 8 September 1943. Appointed by Victor Emmanuel III of Italy, Prince Aimone, Duke of Aosta initially refused to assume the crown in opposition to the Italian annexation of the Croat-majority populated region of Dalmatia. He later accepted the throne upon being pressured to do so by Victor Emmanuel III and was titled Tomislav II of Croatia, but never moved from Italy to reside in Croatia.
The state was actually controlled by the governing fascist Ustaše movement and its Poglavnik, Ante Pavelić.
For its first two years up to 1943, the state was also a territorial condominium of Germany and Italy. Additionally, central Dalmatia was annexed directly into Italian territory as part of the irredentist agenda of an Italian Mare Nostrum ("Our Sea").
In 1942, Germany suggested Italy take military control of all of Croatia out of a desire to redirect German troops from Croatia to the Eastern Front. Italy however rejected the offer as it did not believe that Italy alone could handle the unstable situation in the Balkans.
After the ousting of Mussolini and the Kingdom of Italy's surrender to the Allies, the NDH on 10 September 1943 declared that the Treaties of Rome of 18 May 1941 with the Kingdom of Italy were null and void and annexed the portion of Dalmatia that had been annexed from Yugoslavia to the Kingdom of Italy in the Treaties of Rome.
By early 1945, the NDH army withdrew towards Zagreb with German and Cossack troops. They were overpowered and the advance of Tito's Partisan forces, joined by the Soviet Red Army, caused a mass retreat of the Ustaše towards Austria and effectively an end to the Independent State of Croatia.
The end of the war resulted in the establishment of the Democratic Republic of Yugoslavia, which later became the Socialist Federal Republic of Yugoslavia, with the Constitution of 1946 officially making the People's Republic of Croatia and the People's Republic of Bosnia and Herzegovina two of the six constituent republics of the new state.
Although far right movements in Croatia inspired by the former NDH reemerged during the Croatian War of Independence, the current Constitution of Croatia does not officially recognize the Independent State of Croatia as the historical or legitimate predecessor state of the current Croatian republic.