The independence of Croatia was a process started with the changes in the political system and the constitutional changes in 1990 that transformed the Socialist Republic of Croatia into the Republic of Croatia, which in turn proclaimed the Christmas Constitution, and held the 1991 Croatian independence referendum.

After the country formally declared independence in June 1991 and the dissolution of its association with Yugoslavia, it introduced a three-month moratorium on the decision when urged to do so by the European Community and the Conference on Security and Cooperation in Europe. During that time the Croatian War of Independence started.

On 8 October 1991, the Croatian Parliament severed all remaining ties with Yugoslavia. The Badinter Arbitration Committee had to rule on the matter. Finally, Croatian independence was internationally recognized in January 1992, when both the European Economic Community and the United Nations granted Croatia diplomatic recognition, and the country was accepted into the United Nations shortly thereafter.

During the World War II period from 1941 to 1945, Croatia was established as a puppet state called the Independent State of Croatia, governed by the ultranationalist, fascist Ustaše, backed by Nazi Germany and Fascist Italy within the territory of the Kingdom of Yugoslavia. From 1945 it became a Socialist federal unit of the Socialist Federal Republic of Yugoslavia, a one-party state run by the League of Communists of Croatia created at the end of World War II in Yugoslavia. Croatia enjoyed a degree of autonomy within the Yugoslav federation. At the turn of the 1970s, a Croatian national protest movement called the Croatian Spring was suppressed by Yugoslav leadership. Still, the 1974 Yugoslav Constitution gave increased autonomy to federal units, essentially fulfilling a goal of the Croatian Spring and providing a legal basis for independence of the federative constituents.

In the 1980s, the political situation in Yugoslavia deteriorated, with national tension fanned by the 1986 Serbian SANU Memorandum and the 1989 coups in Vojvodina, Kosovo and Montenegro. As Slovenia and Croatia began to seek greater autonomy within the federation, including confederate status and even full independence, the nationalist ideas started to grow within the ranks of the still-ruling League of Communists. As Slobodan Milošević rose to power in Serbia, his speeches favored continuation of a unified Yugoslav state—one in which all power would be centralized in Belgrade. In March 1989, the crisis in Yugoslavia deepened after the adoption of amendments to the Serbian constitution that allowed the Serbian republic's government to re-assert effective power over the autonomous provinces of Kosovo and Vojvodina. Up until that time, a number of political decisions were legislated from within these provinces, and they had a vote on the Yugoslav federal presidency level (six members from the republics and two members from the autonomous provinces). In the Gazimestan speech, delivered on June 28, 1989, Milošević remarked on the current "battles and quarrels", saying that even though there were currently no armed battles, the possibility could not be excluded yet. The general political situation grew more tense when in 1989 Vojislav Šešelj publicly consorted with Momčilo Đujić, a World War II Chetnik leader. Years later, Croatian Serb leader Milan Babić testified that Momčilo Đujić had financially supported the Serbs in Croatia in the 1990s. Conversely, Franjo Tuđman made international visits during the late 1980s to garner support from the Croatian diaspora for the Croatian national cause.

In mid-1989, political parties other than the Communist Party were first allowed, starting a transition from the one-party system. A number of new parties were founded in Croatia, including the Croatian Democratic Union (Croatian: Hrvatska demokratska zajednica) (HDZ), led by Franjo Tuđman.

In January 1990, the Communist Party fragmented along national lines, with the Croatian faction demanding a looser federation. At the 14th Extraordinary Congress of the League of Communists of Yugoslavia, on 20 January 1990, the delegations of the republics could not agree on the main issues in the Yugoslav federation. The Croatian and Slovenian delegations demanded a looser federation, while the Serbian delegation, headed by Milošević, opposed this. As a result, the Slovenian and Croatian delegates left the Congress. Having completed the anti-bureaucratic revolution in Vojvodina, Kosovo, and Montenegro, Serbia secured four out of eight federal presidency votes in 1991, and it was able to heavily influence decision-making at the federal level, because unfavorable decisions could be blocked; this rendered the governing body ineffective. This situation led to objections from other republics and calls for reform of the Yugoslav Federation.

In February 1990, Jovan Rašković founded the Serb Democratic Party (SDS) in Knin. Its program stated that the "regional division of Croatia is outdated" and that it "does not correspond with the interest of Serb people". The party program endorsed redrawing regional and municipal lines to reflect the ethnic composition of the areas, and asserted the right of territories with a "special ethnic composition" to become autonomous. This echoed Milošević position that internal Yugoslav borders should be redrawn to permit all Serbs to live in a single country. Prominent members of the SDS were Milan Babić and Milan Martić, both of whom later became high-ranking RSK officials. During his later trial, Babić would testify that there was a media campaign directed from Belgrade that portrayed the Serbs in Croatia as being threatened with genocide by the Croat majority and that he fell prey to this propaganda. On 4 March 1990, a meeting of 50,000 Serbs was held at Petrova Gora. People at the rally shouted negative remarks aimed at Tuđman, chanted "This is Serbia", and expressed support for Milošević.