Ueli Steck (Alemannic German: [ˈuεli ʃtɛk]; 4 October 1976 – 30 April 2017) was a Swiss rock climber and alpinist.

[8] On 8 and 9 October 2013 Steck soloed the Lafaille route on the South Face of Annapurna,[9] on the main and highest part of the face;[10] this was his third attempt on the route and has been called "one of the most impressive Himalayan climbs in history",[11] with Steck taking 28 hours to make the trip from Base Camp to summit and back again.

[8] According to mountaineering journalist Rodolphe Popier, who carried out an analysis of Steck's claim and found it questionable, others skeptical of Steck have included former editor-in-chief of German mountaineering magazine Bergsteiger Andreas Kubin, Rolando Garibotti, Alexander and Thomas Huber, fr:Yannick Graziani, Catherine Destivelle, George Lowe, and Leslie Fuczko, former president of the fr:Groupe de Haute Montagne.

[8][15] Christian Trommsdorff, chairman of the Piolet d’Or organizing committee, received several emails from "Swiss-German and German alpinists and journalists" questioning Steck's claim and his nomination for the prize.

[17][13] In the winter of 2014/15, Steck and Michael Wohlleben [de] linked up the three north faces of the Tre Cime di Lavaredo/Drei Zinnen in 16 hours.

[4] Steck died on 30 April 2017 while acclimatizing for an attempt of the Hornbein route on the West Ridge of Everest without supplemental oxygen.

His plan was to climb the Hornbein Couloir to the summit, then proceed with a traverse to the peak of Lhotse, the world's 4th highest mountain.

[27] On 16 April, during preparations for the attempt, his climbing partner, Tenji Sherpa, suffered frostbite, which would take some weeks to heal.

His body was found in the Western Cwm, between camps 1 and 2, and transported back to Kathmandu, where memorial services were held.