The Battle off Samar was the centermost action of the Battle of Leyte Gulf, one of the largest naval battles in history, which took place in the Philippine Sea off Samar Island, in the Philippines on October 25, 1944. As the only major action in the larger battle where the Americans were largely unprepared against the opposing forces, it has been cited by historians as one of the greatest military mismatches in naval history.

In the combined Battle of Leyte Gulf, 10,000 Japanese sailors and 3,000 Americans died. Although the battleship Yamato and the remaining force returned to Japan, the battles marked the final defeat of the Japanese Navy, as the ships remained in port for most of the rest of the war and ceased to be an effective naval force.