Eleven mountaineers from international expeditions died on K2, the second-highest mountain on Earth, in the worst single accident in the history of K2 mountaineering.

The 2008 K2 disaster occurred on 1 August 2008, when 11 mountaineers from international expeditions died on K2, the second-highest mountain on Earth. Three others were seriously injured. The series of deaths, over the course of the Friday ascent and Saturday descent, was the worst single accident in the history of K2 mountaineering. Some of the specific details remain uncertain, with different plausible scenarios having been given about different climbers' timing and actions, and different versions reported later via survivors' eyewitness accounts or via radio communications of climbers who died later in the course of events on K2 that day.