'Arcadia' was the Inter-Allied Washington Conference between Prime Minister Winston Churchill and President Franklin D. Roosevelt (22 December 1941/14 January 1942).

The political successor to the military 'ABC-1' conference, 'Arcadia' decided that the Allies would implement a 'Germany first' policy to ensure the defeat of Germany before that of Japan. Other decisions taken at the conference were that all the Allied military resources in the European theatre would be subordinated to a single command, that a United Nations Organisation would be created (in the 26-nation Declaration of the United Nations on 1 January 1942), and that the British concept for 'Gymnast' would be developed into an Anglo-American 'Super Gymnast' which eventually matured as 'Torch' for implementation toward the end of 1942.

Another major resolution of the 'Arcadia' conference was the establishment of the ABDA (American-British-Dutch-Australian) and ANZAC command structures for the better containment of Japan’s expansion into South-East Asia and the South-West Pacific. As a result of a US suggestion, command of ABDA was entrusted to General Sir Archibald Wavell, who accepted the task on 3 January 1942 and then established his headquarters at Bandoeng in the western half of Java. The ANZAC command was entrusted to Admiral Chester W. Nimitz, Commander-in-Chief Pacific with his headquarters at Pearl Harbor in the Hawaiian islands, with local command of Rear Admiral J. G. Crace’s extemporised force of Australian, New Zealand and US warships exercised by another US Navy officer, Vice Admiral H. F. Leary.

Other outcomes of the conference were the advisability of adding the USSR to the list of nations receiving Lend-Lease aid from the USA, and the despatch of US troops to Iceland and Northern Ireland. Moreover, at the urging of Lord Beaverbrook, Roosevelt and Donald Nelson, executive director of the new War Production board, agreed to a significant increase in the USA’s war matériel production targets. Other matters discussed were the possibility of an Allied invasion of North-West Africa, and General Douglas MacArthur’s urgent pleading for the resources to check the Japanese 'M' (i) advance in the Philippine islands group.