Thma Bang District is a municipality and one of six districts located in the south-west province of Koh Kong, Cambodia. Situated approximately 72 kilometres from central Koh Kong, the district covers an area of 3,465 square kilometres (1,338 mi2). It is bordered by Sre Ambel and Aoral Districts to the east, Koh Kong and Mondol Sima Districts to the west, Velveng and Krovanh Districts to the north, and Botumsakor District to the south.
The district consists of six communes comprising 17 villages. The local economy is primarily driven by agriculture and forest resources, with approximately 98% of the population engaged in farming and hunting for their livelihoods. Additionally, the area serves as a site for conservation efforts, with Conservation International Cambodia maintaining a sub-office within the Thma Bang District to support field activities in the province.