Alison Chadwick-Onyszkiewicz

Alison Chadwick-Onyszkiewicz (1942 – 17 October 1978) was a British climber, mountaineer, painter and lithography lecturer. She made the first ascent of Gasherbrum III, at the time the highest unclimbed mountain in the world. Chadwick-Onyszkiewicz died along with her climbing partner, Vera Watson, during an attempt on Annapurna I Central.

In 1978, she took part in the American Women's Himalayan Expedition to Annapurna, the tenth highest mountain in the world. It consisted of all female climbers, designed to give women the opportunity to climb a major peak at a time when they were often excluded from expeditions. Chadwick-Onyszkiewicz was one of the few non Americans, and was considered one of their best climbers. Annapurna had very few ascents at the time, and they found it to be more treacherous than anticipated, with multiple avalanches causing severe delays in their progress. It is now considered the world's most deadly mountain, with the highest death rate of any 8000er. During the expedition Chadwick-Onyszkiewicz noted "It's the most dangerous mountain I've been on" in a letter to her husband.

In 1972, during the Polish expedition in Hindu Kush, she ascended both Aspe Safed and Noshaq. Based on these climbs, she was selected for the 1975 Polish Gasherbrum Expedition. It was initially designed as a women's only expedition to Gasherbrum III led by Wanda Rutkiewicz, but a simultaneous men's expedition to Gasherbrum II was refused a permit and the two merged. She made the first ascent of Gasherbrum III (7952m), the world's highest unclimbed peak, with a mixed team consisting of her, Rutkiewicz, Onyszkiewicz, and Krzysztof Zdzitowiecki [pl]. During this expedition she gained the British height record for women.

In 1971 Chadwick-Onyszkiewicz married Polish mathematician and mountaineer Janusz Onyszkiewicz, her frequent climbing partner.