'Fivesome' was the Allied cover designation of the multi-national agreement for the co-ordination of all Allied operations in the South-West Pacific Area under the command of General Douglas MacArthur (October 1944/January 1945).

At the 'Fivesome' conference between representatives of the various Allied commands at MacArthur’s headquarters at Hollandia in New Guinea during November 1944, plans for 'Iceberg' and decisions regarding air attacks on Hong Kong and Formosa were agreed.