Ganthems kyrka

The church's oldest fabric survives in the apsidal chancel, dating from the second half of the twelfth century. In the first half of the thirteenth century the two-aisled nave and the tower were added; the nave's east gable was built west of the chancel's original west wall, creating an unusual double triumphal arch where the two building phases meet. A sacristy was added on the north side in 1930.

The exterior is dominated by a tall tower with two storeys of colonnaded sound openings and an octagonal spire. Round-arched window openings appear on the south side, one of which, above the south portal, is original to the building. Further round-arched portals pierce the tower's west wall and the south walls of both nave and chancel. Inside, the nave is covered by four cross-vaults supported on a single central column, with a so-called sound jar built into the apex of the chancel vault, a device thought to have been used to improve acoustics.

The walls carry medieval wall paintings, including a fifteenth-century Passion frieze on the north side that is said never to have been overpainted, an unusual survival compared with most Gotland churches, where later whitewashing typically obscured such decoration. The remaining paintings were uncovered in 1967. A restoration in 1966-67, following proposals by the cathedral architect Eiler Græbe, shaped much of the church's present appearance, alongside earlier changes to pews and a gallery (since removed) made in 1882.

Among the furnishings, the font dates from the twelfth century and is attributed to the so-called Hegvald group of Gotlandic stonemasons. The triumphal crucifix, in Romanesque style, dates from around 1200. The present altarpiece was made in 1901 as a copy of a fourteenth-century original that was sold to the Museum of National Antiquities, while the pulpit dates from 1655.

The organ was built in 1967 by Grönlunds Orgelbyggeri of Gammelstad; it is mechanical, with divided manual stops, and replaced an earlier harmonium used in the church.