Ivittuut Greenlandic pronunciation: [ivitːuːt], (old spelling Ivigtût) was a municipality (from 1951 until 2008), on the coast of Arsuk Fjord in southern Greenland.

With an area of just 100 km2 (600 km2 according to other sources), it was the smallest municipality of Greenland, bordering on the former Narsaq municipality in the north, east and south, and on the west by the Labrador Sea.

Due to its small size, the municipality is all ice-free, as it does not extend inward to the ice sheet of Greenland.

The town of Ivittuut is abandoned and the only settlement of the municipality is the permanent naval base Kangilinnguit (Grønnedal).

Kangilinnguit is the Danish naval headquarters of Greenland, originally established to protect Ivittuut's cryolite mine.