The Romanesque church building is among the oldest in Norway. According to the medieval sagas the first (wooden) church was built on this site in the year 995 by King Olaf Trygvason (Olaf I), who first brought Christianity to Norway. In 1024 King Olav Haraldsson (Olaf II) held an assembly in Moster which decreed the first Christian law.
The present church was partly built from soapstone during the twelfth century and is entirely plastered on the inside and outside.
Both building parts are separated by a transversal wall which has retained its original narrow opening. The medieval altar block in the chancel was equipped with a new altarpiece around 1630.
The present paintings show the Crucifixion (above) and the Last Supper (below) and were carried out in 1825. The baptismal font dates from 1722. The east and north walls of the nave are richly decorated with wall paintings carried out after the Reformation, during the early seventeenth century.
All furnishings in the nave are carried out in the Renaissance style. The pulpit on the south wall is dated to 1637, and the benches on both sides of the central aisle also originated in the seventeenth century. A little later a loft was built over the entrance in the west wall. The nearby visitor centre Moster Amfi has an exhibition on the Christianization of Norway.