The Carter Doctrine was a policy proclaimed by President of the United States Jimmy Carter in his State of the Union Address on January 23, 1980, which stated that the United States would use military force if necessary to defend its national interests in the Persian Gulf region. The doctrine was a response to the 1979 invasion of Afghanistan by the Soviet Union, and was intended to deter the Soviet Union—the Cold War adversary of the United States—from seeking hegemony in the Gulf. After stating that Soviet troops in Afghanistan posed "a grave threat to the free movement of Middle East oil," Carter proclaimed:

This last, key sentence of the Carter Doctrine, was written by Zbigniew Brzezinski, President Carter's National Security Adviser. Brzezinski modeled the wording of the Carter Doctrine on the Truman Doctrine, and insisted that the sentence be included in the speech "to make it very clear that the Soviets should stay away from the Persian Gulf."

In The Prize: The Epic Quest for Oil, Money, and Power, author Daniel Yergin notes that the Carter Doctrine "bore striking similarities" to a 1903 British declaration, in which British Foreign Secretary Lord Landsdowne warned Russia and Germany that the British would "regard the establishment of a naval base or of a fortified port in the Persian Gulf by any other power as a very grave menace to British interests, and we should certainly resist it with all the means at our disposal."