Gunnbjørn Fjeld, Arctic mountain peak in Sermersooq, Greenland.

Gunnbjørn Fjeld is a nunatak in the Watkins Range on Greenland's east coast, a rocky peak rising through glacial ice to about 3,700 metres. Its broad, rounded summit sits above steep dark rock faces marked by horizontal bands of snow and ice, forming stepped terraces. It is the highest mountain in Greenland and north of the Arctic Circle.

Gunnbjørn Fjeld was first climbed on 16 August 1935 by Augustine Courtauld, Jack Longland, Ebbe Munck and Lawrence Wager. The peak lies in the uninhabited Watkins Range on Greenland's east coast, so ascents remain rare and parties usually fly in from Iceland by helicopter or ski-equipped plane.

The mountain is named after Gunnbjörn Ulfsson, the first European to sight Greenland. The name ties the peak to the Norse discovery of the island, and the mountain is climbed only rarely because of its remote location.

The mountain is accessible only by helicopter or ski-equipped aircraft, typically departing from Iceland. The extreme altitude and harsh climate require extensive preparation and specialized mountaineering gear.

Gunnbjørn Fjeld is ranked ninth among the world's most topographically isolated peaks. Its nearest rival of comparable height is Snæfellsjökull in Iceland, 530.2 km away, and the two can normally never be seen at once — only an Arctic mirage, the hillingar effect, might make both visible together.