Greg Mortimer (born 10 December 1952) is an Australian mountaineer. Mortimer is notable as one of the first two Australians (with Tim Macartney-Snape) to successfully climb Mount Everest, on 3 October 1984. Their ascent, without supplemental oxygen, was the first via the North Face and Norton Couloir. It is one of the climbing routes that has not been repeated often.