Petäjävesi Old Church is a UNESCO World Heritage Site located in the town of Petäjävesi, in central Finland. The wooden church was built in 1763 and is considered a masterpiece of Scandinavian Lutheran architecture.

The church is a typical example of the Finnish church style, which is characterized by a cruciform floor plan, a central nave with four aisles, and a sacristy at the east end. It was designed by a local builder, Jaakko Klemetinpoika Leppänen, who combined traditional Finnish building techniques with elements of Baroque architecture.

The church interior is notable for its impressive acoustics, which are created by the vaulted ceilings and the use of spruce for the pews and walls. The altarpiece is a painting of the crucifixion by Mikael Toppelius, and the pulpit, which is in the shape of a ship, is a masterpiece of Finnish woodcarving.

The church is still used for religious services, as well as for concerts and cultural events. It is open to the public during the summer months, and guided tours are available. The Petäjävesi Old Church is an important example of the traditional Finnish wooden architecture and a unique cultural site.