Church of Hvalsey, Medieval church ruin in Kujalleq, Greenland.

The Church of Hvalsey is a stone ruin located in the Kujalleq region of Greenland. The building once measured 16 meters in length and 8 meters in width, and visitors can see the remnants of its original walls.

Hvalsey Church was probably built in the early 14th century, though finds suggest an earlier church on the site. It was one of the 10 to 14 parish churches of the Eastern Settlement, and the sagas say Thorkell Farserk, a relative of Erik the Red, claimed the land. Its last written record is the wedding of Thorstein Olafsson and Sigrid Björnsdóttir in September 1408.

The church hosted the wedding of Thorstein Olafsson and Sigrid Björnsdóttir on 14 or 16 September 1408, recorded in letters from a priest at Garðar and by Icelanders; the couple later settled in Iceland. The site is now part of a sheep farm, and Qaqortoq, "the white place", may take its name from the church's shell-mortar walls.

The church stands about 70 m from the water at the head of Hvalseyjarfjord, on a narrow strip of land near Qaqortoq; the site is now part of a working sheep farm. The walls are roughly 1.5 m thick and the building is roofless, so there is no shelter. Access is by boat or on foot from the fjord, and the ground around the ruin is uneven grass.

The mortar was made from crushed shells, so the church would have been white when built; Qaqortoq, "the white place", may take its name from this association. Some granite fieldstones weigh 4 to 5 tonnes or more. The walls partly collapsed because the church was built over a graveyard whose graves were not removed, causing the foundation to sink.