"Mississippi" supported the invasion of Leyte in October as part of the bombardment group under Rear Admiral Jesse B. Oldendorf. The American invasion triggered the Japanese to launch Operation Shō-Gō 1, a major naval counterattack that resulted in the Battle of Leyte Gulf on 23–26 October, a complex battle that involved four separate actions. She was present at the Battle of Surigao Strait on the night of 24 October, which was one component of the battle. There, the Allied fleet destroyed the Japanese Southern Force consisting of a pair of old battleships, one heavy cruiser, and four destroyers; only one Japanese destroyer escaped the overwhelming Allied fleet. "Mississippi", which still had her old Mark 3 radars, had difficulty in finding a target in the darkness and fired only one salvo in the last battleship action in history.