The Croatian referendum on independence was held in May 1991, with 93% of voters supporting independence. On 25 June, the Croatian Parliament (Sabor) proclaimed Croatian independence. Seven days later, on 7 July, Croatia and Slovenia both signed the Brioni Declaration, in which the two countries agreed to suspend all declarations and acts passed by the Croatian and Slovenian parliaments related to those states' secession from Yugoslavia for a period of three months. During that time, the Croatian War of Independence started.

On 8 October, the Croatian Parliament decided to end relations with Socialist Federal Republic of Yugoslavia, in the Decision on the termination of the state and legal ties with other republics and provinces of Yugoslavia. That session was not held in the House of Parliament but instead in the basement of an INA building, because of the possibility of the repeat of an incident such as the bombing of Banski dvori.

The Government of Ivica Račan moved the Independence Day to 8 October in 2002, and 25 June was marked as a memorial day (working) under the name Statehood Day.

On 14 November 2019, the Croatian Parliament adopted a new law on holidays, and moved Independence Day back to 25 June. Previous date, 8 October, became a working memorial day under the name Day of the Croatian Parliament..
When is Croatian Independence Day?
Croatian Independence Day (Dan Neovisnosti) is celebrated on June 25th. The holiday was established in 2001, but was celebrated on October 8th from 2002 to 2019 which was the day in 1991 when Croatian Parliament declared to end relations with all of the Socialist Republics of Yugoslavia. June 25th, 1991 was the day when Croatian Parliament declared independence from Socialist Federal Republics of Yugoslavia.