The Pearl Harbor advance-knowledge conspiracy theory is the idea that the American officials had advance knowledge of Japan's December 7, 1941 attack on Pearl Harbor. Ever since the Japanese attack there has been debate as to how and why the United States had been caught off guard and how much and when American officials knew of Japanese plans for an attack.

Several writers, including journalist Robert Stinnett and former United States Navy Rear Admiral Robert A. Theobald, have argued that various parties high in the U.S. and British governments knew of the attack in advance and may even have let it happen or encouraged it in order to force America into war via the "back door." Evidence supporting this view is taken from quotations and source documents from the time and the release of newer materials.