Uummannaq fjord, Arctic fjord in Avannaata, Greenland.

Uummannaq Fjord is a large fjord system in northern western Greenland, the largest after Kangertittivaq in eastern Greenland. It runs roughly south-east to west-north-west and empties into Baffin Bay. Its southwestern coast is formed by the Nuussuaq Peninsula; elsewhere the coastline is developed with many bays, islands and peninsulas. Major islands include Upernivik Island, at 540 km2 the largest, and Uummannaq Island, dominated by Uummannaq Mountain.

The fjord area shows signs of early human settlement, with archaeological sites revealing occupation by the Saqqaq culture in ancient times. These early inhabitants left traces that document life in this region over many centuries.

The fjord's name comes from Uummannaq Island's heart-shaped mountain, whose Kalaallisut name means "heart-like." The main town of Uummannaq, once the administrative centre of a municipality covering the whole fjord catchment, now belongs to Avannaata municipality. Smaller island settlements include Ikerasak, Illorsuit, Nuugaatsiaq and Saattut, while Ukkusissat lies on the mainland in the inner fjord.

Reaching the fjord depends on the season, as small aircraft and boats are the main ways to get there. Visitors should prepare for changeable conditions and keep plans flexible.

The fjord area is considered the sunniest spot in Greenland, sheltered from coastal winds by the glaciated mountains of the Nuussuaq Peninsula. Excavations at Qilakitsoq on the Nuussuaq coast revealed the Saqqaq culture, and DNA from human hair suggests these people came from Siberia about 5,500 years ago.