The Sint-Plechelmusbasiliek (Basilica of St. Plechelm) is a Roman Catholic church dedicated to the 8th -century Irish monk Saint Plechelm. The church is a fine example of Romanesque architecture, built entirely from Bentheim sandstone and is most notable for its high pitched roof and bell tower.

The oldest parts of the impressive church date from the middle and second half of the 12th century, but the history of the church goes back to the 8th century when the travelling missionary Plechelmus founded the first church: Sivester church, initially dedicated to pope Sivester and sometime before 954 rededicated to Plechelmus itself (canonised after the elevation of his relics). In 954 bisshop Balderik of Utrecht founded a chapter in Oldenzaal and expanded and restored the 8th -century church, allowing the relics of Plechelmus used on his canonisation to be transferred to it.

The current tower was erected around 1240. The church was enlarged in Gothic style in 1480s. Through the years the Sint-Plechelmusbasiliek has undergone a number of renovations and repairs, however most of its structure still boasts of its original features.