Old Moster Church is a parish church of the Church of Norway in Bømlo Municipality in Vestland county, Norway, and it is one of the oldest churches in all of Norway. It is located in the village of Mosterhamn on the island of Moster. It used to be the main church for the Moster parish which is part of the Sunnhordland prosti (deanery) in the Diocese of Bjørgvin. The white stone church was built in a long church design in the 12th century using plans drawn up by an unknown architect. The church seats about 80 people.