English: Diadem Peak (elevation: 3,371 m, 11,060 ft) is a peak located in the Sunwapta River Valley of Jasper National Park, Canada.

Diadem Peak is essentially the high point of a ridge leading down from the slightly higher Mount Woolley (3,405 m, 11,171 ft). This peak was the first 11,000er north of the Columbia Icefield to be climbed, and one of the few peaks in the Canadian Rockies to be climbed before 1900.

The mountain was named in 1898 by the first ascent team of J. Norman Collie, Hugh Stutfield and Hermann Woolley.

Upon reaching the summit, they discovered a crown (diadem) of snow about 30 m (98 ft) high covering the almost flat layer of rocks on top.