The Ok Tedi Mine is an open-pit copper and gold mine in Papua New Guinea located near the headwaters of the Ok Tedi River, in the Star Mountains Rural LLG of the North Fly District of the Western Province of Papua New Guinea. Discharges from the mine have caused widespread and diverse harm, both environmentally and socially, to the 50,000 people who live in the 120 villages downstream of the mine.
The mine is operated by Ok Tedi Mining Limited (OTML), which is majority-owned by the PNG Sustainable Development Program Limited (PNGSDPL). In 2013 it was nationalised by the Government of Papua New Guinea in controversial action. Prior to 2002, it was majority owned by BHP Billiton, the largest mining company in the world since a merger in 2001.