The First Battle of Changsha was the first of four attempts by Japan to take the city of Changsha, Hunan, during the second Sino-Japanese War. Coming two weeks after Germany's invasion of Poland on September 1, it was the first major battle of the war to fall within the time frame of what is widely considered World War II.

Changsha is the capital and the largest city of Hunan Province of China. Changsha is the 17th most populous city in China with a population of over 10 million, and the third-most populous city in Central China, located in the lower reaches of the Xiang River in northeastern Hunan. Changsha is also called Xingcheng and was once named Linxiang, Tanzhou, and Qingyang (青阳) in ancient times. It is also known as Shanshuizhoucheng (山水洲城), with the Xiang River flowing through it, containing Mount Yuelu and Orange Isle. The city forms a part of the Greater Changsha Metropolitan Region along with Zhuzhou and Xiangtan, also known as Changzhutan City Cluster. Greater Changsha was named one of the 13 emerging mega-cities in China in 2012 by the Economist Intelligence Unit. It is also a National Comprehensive Transportation Hub, and one of the first National Famous Historical and Cultural Cities in China. Changshanese, a kind of Xiang Chinese, is spoken in the downtown, while Ningxiangnese and Liuyangnese are also spoken in the counties and cities under its jurisdiction. As of the 2020 Chinese census, the prefecture-level city of Changsha had a population of 10,047,914 inhabitants.