The Battle of Manila was a major battle of the Philippine campaign of 1944–45, during the Second World War. It was fought by forces from both the United States and the Philippines against Japanese troops in Manila, the capital city of the Philippines. The month-long battle, which resulted in the death of at least 100,000 civilians and the complete devastation of the city, was the scene of the worst urban fighting fought by American forces in the Pacific theater. During the battle, Japanese forces committed mass murder against Filipino civilians, while American firepower killed many people. The resistance of the Japanese and American artillery also destroyed much of Manila's architectural and cultural heritage dating back to the city's founding. The battle is widely considered to be one of the most intense and worst urban battles ever fought, with it being the single largest urban battle ever fought by American forces.

Manila, officially the City of Manila, is the capital and second-most-populous city of the Philippines. Located on the eastern shore of Manila Bay on the island of Luzon, it is classified as a highly urbanized city. As of 2019, it is the world's most densely populated city proper. It was the first chartered city in the country, and was designated as such by the Philippine Commission Act No. 183 on July 31, 1901. It became autonomous with the passage of Republic Act No. 409, "The Revised Charter of the City of Manila", on June 18, 1949. Manila is considered to be part of the world's original set of global cities because its commercial networks were the first to extend across the Pacific Ocean and connect Asia with the Spanish Americas through the galleon trade; when this was accomplished, it was the first time an uninterrupted chain of trade routes circling the planet had been established.