Lieutenant Colonel James Owen Merion Roberts MVO MBE MC (21 September 1916 – 1 November 1997) was one of the greatest Himalayan mountaineer-explorers of the twentieth century; a highly decorated British Army officer who achieved his greatest renown as "the father of trekking" in Nepal. His exploratory activities are comparable to those of Eric Shipton and Bill Tilman.

Born in Gujarat, India on 21 September 1916 to Henry and Helen Roberts, Roberts spent his early life in India, where his father was a headmaster. After attending King's School, Canterbury and then the Royal Military College, Sandhurst, he was commissioned onto the Unattached List for the Indian Army in August 1936 as a 19-year-old subaltern to satisfy his ardent craving for mountaineering. After a probationary year attached to the 1st Battalion, the East Yorkshire Regiment in India, he was posted to the 1st battalion, 1st (King George V's Own) Gurkha Rifles in November 1937.

His first major expedition was the J. Waller-led attempt in 1938 on Masherbrum, 7890 metres, in the Karakorams: the weather was bad, the attempt was unsuccessful and J.B. Harrison and R.A. Hodgkin got severely frostbitten. Roberts himself suffered at high altitude and suffered mild frostbite.

He tried to join the post-monsoon 1939 Everest expedition led by Bill Tilman, but the attempt was called off. That year, he recorded the first of his many first ascents, that of Guan Nelda, 6303 metres (now called Chau Chau Kang Nilda) in the Spiti Himalaya. The ascent was remarkable for something which became a Roberts hallmark: he climbed without any other "sahib" for company, accompanied only by his Gurkhas. In this he was the true successor of the legendary Dr. A. M. Kellas who had climbed in the same fashion in Sikkim before 1914.

He was selected for the abortive 1940 Everest expedition.

The second major first ascent by Roberts was the 1941 climb of the 6431 metres/21,100 peak locally called Dharmsura in the Tos Glacier of Kullu Himalaya. He named it White Sail.