The Israeli Declaration of Independence, formally the Declaration of the Establishment of the State of Israel (Hebrew: הכרזה על הקמת מדינת ישראל), was proclaimed on 14 May 1948 (5 Iyar 5708), at the end of the civil war phase and beginning of the international phase of the 1948 Palestine war, by David Ben-Gurion, the Executive Head of the World Zionist Organization and Chairman of the Jewish Agency for Palestine.

It declared the establishment of a Jewish state in Palestine (or the Land of Israel in the Jewish tradition), to be known as the State of Israel, which would come into effect on termination of the British Mandate at midnight that day. The event is celebrated annually in Israel as Independence Day, a national holiday on 5 Iyar of every year according to the Hebrew calendar.

The possibility of a Jewish homeland in Palestine had been a goal of Zionist organisations since the late 19th century. In 1917 British foreign secretary Arthur Balfour stated in a letter to British Jewish community leader Walter, Lord Rothschild that:

His Majesty's government view with favour the establishment in Palestine of a national home for the Jewish people, and will use their best endeavours to facilitate the achievement of this object, it being clearly understood that nothing shall be done which may prejudice the civil and religious rights of existing non-Jewish communities in Palestine, or the rights and political status enjoyed by Jews in any other country.

Through this letter, which became known as the Balfour Declaration, British government policy officially endorsed Zionism. After World War I, the United Kingdom was given a mandate for Palestine, which it had conquered from the Ottomans during the war. In 1937 the Peel Commission suggested partitioning Mandate Palestine into an Arab state and a Jewish state, though the proposal was rejected as unworkable by the government and was at least partially to blame for the renewal of the 1936–39 Arab revolt.

In the face of increasing violence after World War II, the British handed the issue over to the recently established United Nations. The result was Resolution 181(II), a plan to partition Palestine into Independent Arab and Jewish States and the Special International Regime for the City of Jerusalem. The Jewish state was to receive around 56% of the land area of Mandate Palestine, encompassing 82% of the Jewish population, though it would be separated from Jerusalem. The plan was accepted by most of the Jewish population, but rejected by much of the Arab populace. On 29 November 1947, the resolution to recommend to the United Kingdom, as the mandatory Power for Palestine, and to all other Members of the United Nations the adoption and implementation, with regard to the future government of Palestine, of the Plan of Partition with Economic Union was put to a vote in the United Nations General Assembly.

The result was 33 to 13 in favour of the resolution, with 10 abstentions. Resolution 181(II): PART I: Future constitution and government of Palestine: A. TERMINATION OF MANDATE, PARTITION AND INDEPENDENCE: Clause 3 provides:

Independent Arab and Jewish States and the Special International Regime for the City of Jerusalem, ... shall come into existence in Palestine two months after the evacuation of the armed forces of the mandatory Power has been completed but in any case not later than 1 October 1948.