The original building consisted of a nave with a straight-ended chancel to the east and a west tower, typical of Romanesque parish churches in the region. In the early 1700s the church was substantially enlarged with wide transepts, built under the direction of stonemason Per Jonsson on the instructions of Bishop Jesper Svedberg: the north transept between 1721 and 1729, and the south between 1733 and 1737. This work altered the orientation of the interior, with the chancel then facing south rather than east, and ceiling paintings by Olof Collander and Johan Liedholm were added at this time.
Unusually, Västerplana kyrka has been spared the large-scale restorations that reshaped many Swedish churches in later centuries; apart from routine maintenance, little has changed since the 1730s.
The church's most striking story is its abandonment. During the 1820s it fell out of use and stood empty for more than a hundred years. A royal order of 1821 decreed that the building should be demolished within fifty years, but local parishioners refused to tear it down, sacrificing only the sacristy to decay. Accounts describe the nave in this period as open to the elements, with a birch tree growing inside and birds flying freely through broken windows. Restoration work began around the turn of the twentieth century, and the church was reconsecrated by Bishop Hjalmar Danell on 7 December 1924.
Among the furnishings is a sandstone font with a cylindrical bowl dating from the 1100s, carved with eight figurative panels in the style associated with the so-called Bestiarius master. A seated wooden Madonna figure, carved from lime wood and dated to the period 1225–1300, and an early fifteenth-century wooden figure of John the Baptist holding an Agnus Dei medallion are also kept in the church. The pulpit dates from 1636, and a medieval triumphal crucifix hangs on the wall behind it. Two late-medieval bells, both without inscriptions, still hang in the tower, and the church has a small organ built in 1961.