Tasiusaq is a settlement in the Kujalleq municipality in southern Greenland, founded in 1933. It is located at the Tasermiut Fjord, east of Nanortalik. Its population was 53 in 2020. In the Greenlandic language, the name of the settlement means "like a lake", referring to the lake-looking bay it's situated on. The inhabitants call it "Tasiisaq", which is the local dialect.