Francis Sydney Smythe, better known as Frank Smythe or F. S. Smythe (6 July 1900 - 27 June 1949), was an English mountaineer, author, photographer and botanist. He is best remembered for his mountaineering in the Alps as well as in the Himalayas, where he identified a region that he named the Valley of Flowers, now a protected park. His ascents include two new routes on the Brenva Face of Mont Blanc, Kamet, and attempts on Kangchenjunga and Mount Everest in the 1930s. It was said that he had a tendency for irascibility, something some of his mountaineering contemporaries said decreased with altitude.