St. Martins-Kirche, Roman Catholic parish church in Oberwesel, Germany

St. Martin's Church stands on the highest point of Oberwesel, its white nave contrasting with a tall square tower of rough brown stone. The tower, once part of the town fortifications, has a crenellated top and an octagonal bell chamber above. The nave has a steep dark roof with small dormer windows and tall pointed windows along its side.

A collegiate foundation established in 1303 under Archbishop Diether of Nassau built the church; the foundation was destroyed in the Thirty Years' War. The present building was largely erected in the first half of the 14th century, modelled on Oberwesel's Liebfrauenkirche. After the Wesel War of 1390–1391 the tower was refortified with battlements and corner turrets; a wall anchor in its upper storey was dendrochronologically dated to 1435.

The church has served as the spiritual heart of Oberwesel for centuries and continues to define the town's skyline today. Its tower acts as a natural landmark that guides visitors moving through the medieval streets below.

The church stands on the highest point north of the old town, so its tower is a reliable landmark when navigating Oberwesel. The main nave is entered from the west side, where a low stone wall and black metal gate open onto the churchyard. The parish garden is part of the Welterbe-Gärten route.

The high altar's four-storey Baroque superstructure of 1682 stands over a Gothic mensa; its paintings show the Descent from the Cross, the Vera Icon, the Coronation of Mary and the apostles Peter and Paul. In the side aisle, a gravestone depicts Katharina Feist, who died in 1522.