Cho Oyu (or Cho Oyo or Mt. Zhuoaoyou) is the sixth highest mountain in the world. Cho Oyu lies in the Himalaya and is 20km west of Mount Everest. Cho Oyu means "Turquoise Goddess" in Tibetan.

Cho Oyu was first climbed on October 19, 1954 via the northwest ridge by Herbert Tichy, Joseph Joechler and Sherpa Pasang Dawa Lama of an Austrian expedition. Cho Oyu was first attempted in 1952 by an expedition led by Eric Shipton, but technical difficulties at an ice cliff above 6,650m (21,820ft) proved beyond their abilities. Today, these ice cliffs are normally ascended using fixed ropes.

Cho Oyo is located 20 km west of Mount Everest.Just a few kilometres west of Cho Oyu is Nangpa La (5,716m/18,753ft), a glaciated pass that serves as the main trading route between the Tibetans and the Khumbu's Sherpas. Due to its close proximity to this pass, climbers consider Cho Oyu the easiest 8,000m peak to climb. Cho Oyu was the fifth 8,000m peak to be climbed after Annapurna in June 1950, Mount Everest in May 1953, Nanga Parbat in July 1953 and K2 in July 1954.

Cho Oyu is the sixth highest mountain in the world, located a short distance to the west from Everest (the highest) and Lhotse (the fourth highest) in the Khumbu region of Eastern Nepal along the Tibetan border. Its towering peak stands with Everest well above the surrounding mountains. It became a familiar landmark to climbers ascending Everest's north face. Just west of Cho Oyu is the Nangpa La, a 19,000-foot glacier pass, the main trade route between the Khumbu Sherpas and Tibet. Cho Oyu's proximity to the Nangpa La has earned it the distinction among some climbers as being the easiest 8,000 meter peak. It was the third such peak climbed, and the first climbed in Autumn.