Timmiarmiit (old spelling 'Tingmiarmit') is an uninhabited island of the King Frederick VI Coast, Sermersooq municipality, southern Greenland.

The island is located at the entrance of the Timmiarmiut Fjord in a very indented area of King Frederick VI Coast in southeastern Greenland.

Timmiarmiit's coastline is very irregular with a deep fjord on its eastern side that almost divides the island in two.

[1] It is separated from the mainland in the north by the Timmiarmiit Tunorqútariât, a narrow sound.

Off its southern shoreline lie the islands of Aaluik and Ingmikârtajivit, as well as a multitude of islets and rocks.