Cho Oyu (Nepali: चोयु; Tibetan: ཇོ་བོ་དབུ་ཡ) is the sixth highest mountain in the world at 8,188 metres (26,864 ft) above sea level. Cho Oyu means "Turquoise Goddess" in Tibetan. The mountain is the westernmost major peak of the Khumbu sub-section of the Mahalangur Himalaya 20 km west of Mount Everest. The mountain stands on the China-Nepal border.

Just a few kilometres west of Cho Oyu is Nangpa La (5,716m/18,753 ft), a glaciated pass that serves as the main trading route between the Tibetans and the Khumbu's Sherpas. This pass separates the Khumbu and RolwalingHimalayas. Due to its proximity to this pass and the generally moderate slopes of the standard northwest ridge route, Cho Oyu is considered the easiest 8,000 metre peak to climb.[2] It is a popular objective for professionally guided parties.