The Preamble to the United Nations Charter is the opening (preamble) of the 1945 United Nations Charter.

Jan Smuts from South Africa originally wrote the opening lines of the Preamble as, "The High Contracting Parties, determined to prevent a recurrence of the fratricidal strife which twice in our generation has brought untold sorrow and loss upon mankind. . ." which would have been similar to the opening lines of the Covenant of the League of Nations. After considerable argument at the United Nations Conference on International Organization, held in San Francisco, particularly Soviet insistence that language regarding the equal rights and self-determination of peoples be included in the Charter, the Preamble was modified significantly.

The opening phrase "We the peoples of the United Nations ..", echoing the preamble of the United States Constitution, was suggested by US conference delegates Virginia Gildersleeve and Sol Bloom. The preambulatory phrase "In Larger Freedom" became the title of a UN reform proposal by the seventh Secretary-General, Kofi Annan.

The Preamble reads as follows:

Accordingly, our respective Governments, through representatives assembled in the city of San Francisco, who have exhibited their full powers found to be in good and due form, have agreed to the present Charter of the United Nations and do hereby establish an international organization to be known as the United Nations.